diff --git a/scripts/langindex.json b/scripts/langindex.json
index 4a31ebf4178..272d14f62e8 100644
--- a/scripts/langindex.json
+++ b/scripts/langindex.json
@@ -1148,9 +1148,22 @@
   "addon.privatefiles.files": "moodle",
   "addon.privatefiles.privatefiles": "moodle",
   "addon.privatefiles.sitefiles": "moodle",
+  "addon.qtype_ddimageortext.pleasedraganimagetoeachdropregion": "qtype_ddimageortext",
+  "addon.qtype_ddmarker.pleasedragatleastonemarker": "qtype_ddmarker",
   "addon.qtype_essay.maxwordlimitboundary": "qtype_essay",
   "addon.qtype_essay.minwordlimitboundary": "qtype_essay",
+  "addon.qtype_gapselect.pleaseputananswerineachbox": "qtype_gapselect",
+  "addon.qtype_match.pleaseananswerallparts": "qtype_match",
+  "addon.qtype_multianswer.pleaseananswerallparts": "qtype_multianswer",
+  "addon.qtype_multichoice.pleaseselectananswer": "qtype_multichoice",
+  "addon.qtype_multichoice.pleaseselectatleastoneanswer": "qtype_multichoice",
+  "addon.qtype_numerical.invalidnumber": "qtype_numerical",
+  "addon.qtype_numerical.invalidnumbernounit": "qtype_numerical",
+  "addon.qtype_numerical.pleaseenterananswer": "qtype_numerical",
+  "addon.qtype_numerical.unitnotselected": "qtype_numerical",
   "addon.qtype_ordering.moved": "qtype_ordering",
+  "addon.qtype_shortanswer.pleaseenterananswer": "qtype_shortanswer",
+  "addon.qtype_truefalse.pleaseselectananswer": "qtype_truefalse",
   "addon.report_insights.actionsaved": "report_insights",
   "addon.report_insights.fixedack": "analytics",
   "addon.report_insights.incorrectlyflagged": "analytics",
diff --git a/src/addons/mod/book/pages/contents/contents.html b/src/addons/mod/book/pages/contents/contents.html
index 83191f3c514..a03124df1d2 100644
--- a/src/addons/mod/book/pages/contents/contents.html
+++ b/src/addons/mod/book/pages/contents/contents.html
@@ -10,7 +10,7 @@ <h1>
         </ion-title>
         <ion-buttons slot="end">
             <ion-button (click)="showToc()" [ariaLabel]="'addon.mod_book.toc' | translate" aria-haspopup="true" *ngIf="loaded">
-                <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
             </ion-button>
         </ion-buttons>
     </ion-toolbar>
diff --git a/src/addons/mod/book/tests/behat/snapshots/test-basic-usage-of-book-activity-in-app-open-chapters-from-table-of-contents_11.png b/src/addons/mod/book/tests/behat/snapshots/test-basic-usage-of-book-activity-in-app-open-chapters-from-table-of-contents_11.png
index 41667409394..63dc621e5d9 100644
Binary files a/src/addons/mod/book/tests/behat/snapshots/test-basic-usage-of-book-activity-in-app-open-chapters-from-table-of-contents_11.png and b/src/addons/mod/book/tests/behat/snapshots/test-basic-usage-of-book-activity-in-app-open-chapters-from-table-of-contents_11.png differ
diff --git a/src/addons/mod/imscp/pages/view/view.html b/src/addons/mod/imscp/pages/view/view.html
index 611732ec94d..6e6eb66eede 100644
--- a/src/addons/mod/imscp/pages/view/view.html
+++ b/src/addons/mod/imscp/pages/view/view.html
@@ -11,7 +11,7 @@ <h1>
 
         <ion-buttons slot="end">
             <ion-button *ngIf="loaded" (click)="showToc()" aria-haspopup="true" [ariaLabel]="'addon.mod_imscp.toc' | translate">
-                <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
             </ion-button>
         </ion-buttons>
     </ion-toolbar>
diff --git a/src/addons/mod/lesson/pages/player/player.html b/src/addons/mod/lesson/pages/player/player.html
index f56047a6c41..0e2166e3583 100644
--- a/src/addons/mod/lesson/pages/player/player.html
+++ b/src/addons/mod/lesson/pages/player/player.html
@@ -11,7 +11,7 @@ <h1>
         <ion-buttons slot="end">
             <ion-button fill="clear" *ngIf="displayMenu || mediaFile" [ariaLabel]="'addon.mod_lesson.lessonmenu' | translate"
                 (click)="showMenu()">
-                <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
             </ion-button>
         </ion-buttons>
     </ion-toolbar>
diff --git a/src/addons/mod/quiz/accessrules/password/services/handlers/password.ts b/src/addons/mod/quiz/accessrules/password/services/handlers/password.ts
index 7e0fec67f2e..5ff4cc59a7e 100644
--- a/src/addons/mod/quiz/accessrules/password/services/handlers/password.ts
+++ b/src/addons/mod/quiz/accessrules/password/services/handlers/password.ts
@@ -32,14 +32,7 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
     ruleName = 'quizaccess_password';
 
     /**
-     * Add preflight data that doesn't require user interaction. The data should be added to the preflightData param.
-     *
-     * @param quiz The quiz the rule belongs to.
-     * @param preflightData Object where to add the preflight data.
-     * @param attempt The attempt started/continued. If not supplied, user is starting a new attempt.
-     * @param prefetch Whether the user is prefetching the quiz.
-     * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done if async, void if it's synchronous.
+     * @inheritdoc
      */
     async getFixedPreflightData(
         quiz: AddonModQuizQuizWSData,
@@ -76,33 +69,21 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
     }
 
     /**
-     * Return the Component to use to display the access rule preflight.
-     * Implement this if your access rule requires a preflight check with user interaction.
-     * It's recommended to return the class of the component, but you can also return an instance of the component.
-     *
-     * @returns The component (or promise resolved with component) to use, undefined if not found.
+     * @inheritdoc
      */
     getPreflightComponent(): Type<unknown> | Promise<Type<unknown>> {
         return AddonModQuizAccessPasswordComponent;
     }
 
     /**
-     * Whether or not the handler is enabled on a site level.
-     *
-     * @returns True or promise resolved with true if enabled.
+     * @inheritdoc
      */
     async isEnabled(): Promise<boolean> {
         return true;
     }
 
     /**
-     * Whether the rule requires a preflight check when prefetch/start/continue an attempt.
-     *
-     * @param quiz The quiz the rule belongs to.
-     * @param attempt The attempt started/continued. If not supplied, user is starting a new attempt.
-     * @param prefetch Whether the user is prefetching the quiz.
-     * @param siteId Site ID. If not defined, current site.
-     * @returns Whether the rule requires a preflight check.
+     * @inheritdoc
      */
     async isPreflightCheckRequired(
         quiz: AddonModQuizQuizWSData,
@@ -117,14 +98,7 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
     }
 
     /**
-     * Function called when the preflight check has passed. This is a chance to record that fact in some way.
-     *
-     * @param quiz The quiz the rule belongs to.
-     * @param attempt The attempt started/continued.
-     * @param preflightData Preflight data gathered.
-     * @param prefetch Whether the user is prefetching the quiz.
-     * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done if async, void if it's synchronous.
+     * @inheritdoc
      */
     async notifyPreflightCheckPassed(
         quiz: AddonModQuizQuizWSData,
@@ -135,21 +109,14 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
     ): Promise<void> {
         // The password is right, store it to use it automatically in following executions.
         if (preflightData.quizpassword !== undefined) {
-            return this.storePassword(quiz.id, preflightData.quizpassword, siteId);
+            await this.storePassword(quiz.id, preflightData.quizpassword, siteId);
         }
     }
 
     /**
-     * Function called when the preflight check fails. This is a chance to record that fact in some way.
-     *
-     * @param quiz The quiz the rule belongs to.
-     * @param attempt The attempt started/continued.
-     * @param preflightData Preflight data gathered.
-     * @param prefetch Whether the user is prefetching the quiz.
-     * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done if async, void if it's synchronous.
+     * @inheritdoc
      */
-    notifyPreflightCheckFailed?(
+    async notifyPreflightCheckFailed?(
         quiz: AddonModQuizQuizWSData,
         attempt: AddonModQuizAttemptWSData | undefined,
         preflightData: Record<string, string>,
@@ -157,7 +124,7 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
         siteId?: string,
     ): Promise<void> {
         // The password is wrong, remove it from DB if it's there.
-        return this.removePassword(quiz.id, siteId);
+        await this.removePassword(quiz.id, siteId);
     }
 
     /**
@@ -165,7 +132,6 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
      *
      * @param quizId Quiz ID.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     protected async removePassword(quizId: number, siteId?: string): Promise<void> {
         const site = await CoreSites.getSite(siteId);
@@ -179,7 +145,6 @@ export class AddonModQuizAccessPasswordHandlerService implements AddonModQuizAcc
      * @param quizId Quiz ID.
      * @param password Password.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     protected async storePassword(quizId: number, password: string, siteId?: string): Promise<void> {
         const site = await CoreSites.getSite(siteId);
diff --git a/src/addons/mod/quiz/components/index/index.ts b/src/addons/mod/quiz/components/index/index.ts
index 30515e84b40..112f1af1b07 100644
--- a/src/addons/mod/quiz/components/index/index.ts
+++ b/src/addons/mod/quiz/components/index/index.ts
@@ -130,8 +130,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
     /**
      * Attempt the quiz.
-     *
-     * @returns Promise resolved when done.
      */
     async attemptQuiz(): Promise<void> {
         if (this.showStatusSpinner || !this.quiz) {
@@ -141,7 +139,9 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
         if (!AddonModQuiz.isQuizOffline(this.quiz)) {
             // Quiz isn't offline, just open it.
-            return this.openQuiz();
+            this.openQuiz();
+
+            return;
         }
 
         // Quiz supports offline, check if it needs to be downloaded.
@@ -150,7 +150,9 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
         if (isDownloaded) {
             // Already downloaded, open it.
-            return this.openQuiz();
+            this.openQuiz();
+
+            return;
         }
 
         // Prefetch the quiz.
@@ -242,7 +244,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
      * Get the user attempts in the quiz and the result info.
      *
      * @param quiz Quiz instance.
-     * @returns Promise resolved when done.
      */
     protected async getAttempts(
         quiz: AddonModQuizQuizData,
@@ -326,7 +327,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
      * Get result info to show.
      *
      * @param quiz Quiz.
-     * @returns Promise resolved when done.
      */
     protected async getResultInfo(quiz: AddonModQuizQuizData): Promise<void> {
         if (!this.attempts.length || !quiz.showAttemptsGrades || !this.bestGrade?.hasgrade ||
@@ -382,8 +382,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
     /**
      * Go to review an attempt that has just been finished.
-     *
-     * @returns Promise resolved when done.
      */
     protected async goToAutoReview(attempts: AddonModQuizAttemptWSData[]): Promise<void> {
         if (!this.autoReview) {
@@ -505,10 +503,10 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
     /**
      * Open a quiz to attempt it.
      */
-    protected openQuiz(): void {
+    protected async openQuiz(): Promise<void> {
         this.hasPlayed = true;
 
-        CoreNavigator.navigateToSitePath(
+        await CoreNavigator.navigateToSitePath(
             `${ADDON_MOD_QUIZ_PAGE_NAME}/${this.courseId}/${this.module.id}/player`,
             {
                 params: {
@@ -554,7 +552,7 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
      * @param quiz Quiz data.
      * @param accessInfo Quiz access information.
      * @param attempts The attempts to treat.
-     * @returns Promise resolved when done.
+     * @returns Formatted attempts.
      */
     protected async treatAttempts(
         quiz: AddonModQuizQuizData,
@@ -630,8 +628,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
     /**
      * Get quiz grade data.
-     *
-     * @returns Promise resolved when done.
      */
     protected async getQuizGrade(): Promise<void> {
         try {
@@ -656,8 +652,6 @@ export class AddonModQuizIndexComponent extends CoreCourseModuleMainActivityComp
 
     /**
      * Go to page to review the attempt.
-     *
-     * @returns Promise resolved when done.
      */
     async reviewAttempt(attemptId: number): Promise<void> {
         await CoreNavigator.navigateToSitePath(
diff --git a/src/addons/mod/quiz/constants.ts b/src/addons/mod/quiz/constants.ts
index 67bd89826cc..8dc0d8775c5 100644
--- a/src/addons/mod/quiz/constants.ts
+++ b/src/addons/mod/quiz/constants.ts
@@ -54,3 +54,11 @@ export const enum AddonModQuizDisplayOptionsAttemptStates {
     LATER_WHILE_OPEN = 0x00100,
     AFTER_CLOSE = 0x00010,
 }
+
+/**
+ * Possible navigation methods for a quiz.
+ */
+export const enum AddonModQuizNavMethods {
+    FREE = 'free',
+    SEQ = 'sequential',
+}
diff --git a/src/addons/mod/quiz/pages/player/player.html b/src/addons/mod/quiz/pages/player/player.html
index 899bd0cfbae..60572189665 100644
--- a/src/addons/mod/quiz/pages/player/player.html
+++ b/src/addons/mod/quiz/pages/player/player.html
@@ -15,9 +15,9 @@ <h1>
                 (click)="showConnectionError($event)" [ariaLabel]="'addon.mod_quiz.connectionerror' | translate" aria-haspopup="dialog">
                 <ion-icon name="fas-circle-exclamation" slot="icon-only" aria-hidden="true" />
             </ion-button>
-            <ion-button *ngIf="navigation.length && !showSummary" [ariaLabel]="'addon.mod_quiz.opentoc' | translate"
+            <ion-button *ngIf="attemptSummary.length && !showSummary" [ariaLabel]="'addon.mod_quiz.opentoc' | translate"
                 (click)="openNavigation()">
-                <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
             </ion-button>
         </ion-buttons>
     </ion-toolbar>
@@ -64,13 +64,13 @@ <h1>
         </ion-row>
 
         <!-- Summary -->
-        <ion-card *ngIf="!quizAborted && showSummary && summaryQuestions.length" class="addon-mod_quiz-table">
+        <ion-card *ngIf="!quizAborted && showSummary && attemptSummary.length" class="addon-mod_quiz-table">
             <ion-card-header class="ion-text-wrap">
                 <ion-card-title>{{ 'addon.mod_quiz.summaryofattempt' | translate }}</ion-card-title>
             </ion-card-header>
 
             <!-- List of questions of the summary table. -->
-            <ng-container *ngFor="let question of summaryQuestions">
+            <ng-container *ngFor="let question of attemptSummary">
                 <ion-item *ngIf="question.type !== 'description' && question.questionnumber"
                     (click)="!isSequential && canReturn && changePage(question.page, false, question.slot)"
                     [detail]="!isSequential && canReturn" [button]="!isSequential && canReturn"
@@ -123,7 +123,7 @@ <h1>
             </ion-button>
         </ion-card>
 
-        <div collapsible-footer appearOnBottom *ngIf="!quizAborted && showSummary && summaryQuestions.length && loaded" slot="fixed">
+        <div collapsible-footer appearOnBottom *ngIf="!quizAborted && showSummary && attemptSummary.length && loaded" slot="fixed">
             <div class="list-item-limited-width">
                 <ion-button *ngIf="preventSubmitMessages.length" expand="block" class="ion-margin ion-text-wrap" [href]="moduleUrl"
                     core-link [showBrowserWarning]="false">
diff --git a/src/addons/mod/quiz/pages/player/player.ts b/src/addons/mod/quiz/pages/player/player.ts
index 3eaadd32529..3f5fb9325a7 100644
--- a/src/addons/mod/quiz/pages/player/player.ts
+++ b/src/addons/mod/quiz/pages/player/player.ts
@@ -20,7 +20,6 @@ import { CoreIonLoadingElement } from '@classes/ion-loading';
 import { CoreQuestionComponent } from '@features/question/components/question/question';
 import {
     CoreQuestionQuestionForView,
-    CoreQuestionQuestionParsed,
     CoreQuestionsAnswers,
 } from '@features/question/services/question';
 import { CoreQuestionBehaviourButton, CoreQuestionHelper } from '@features/question/services/question-helper';
@@ -78,12 +77,11 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
     loaded = false; // Whether data has been loaded.
     quizAborted = false; // Whether the quiz was aborted due to an error.
     offline = false; // Whether the quiz is being attempted in offline mode.
-    navigation: AddonModQuizNavigationQuestion[] = []; // List of questions to navigate them.
+    attemptSummary: AddonModQuizNavigationQuestion[] = []; // Attempt summary: list of questions to navigate.
     questions: CoreQuestionQuestionForView[] = []; // Questions of the current page.
     nextPage = -2; // Next page.
     previousPage = -1; // Previous page.
     showSummary = false; // Whether the attempt summary should be displayed.
-    summaryQuestions: CoreQuestionQuestionParsed[] = []; // The questions to display in the summary.
     canReturn = false; // Whether the user can return to a page after seeing the summary.
     preventSubmitMessages: string[] = []; // List of messages explaining why the quiz cannot be submitted.
     endTime?: number; // The time when the attempt must be finished.
@@ -266,24 +264,23 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
      * @param page Page to load. -1 means summary.
      * @param fromModal Whether the page was selected using the navigation modal.
      * @param slot Slot of the question to scroll to.
-     * @returns Promise resolved when done.
      */
     async changePage(page: number, fromModal?: boolean, slot?: number): Promise<void> {
         if (!this.attempt) {
             return;
         }
 
-        if (page != -1 && (this.attempt.state === AddonModQuizAttemptStates.OVERDUE || this.attempt.finishedOffline)) {
+        if (page !== -1 && (this.attempt.state === AddonModQuizAttemptStates.OVERDUE || this.attempt.finishedOffline)) {
             // We can't load a page if overdue or the local attempt is finished.
             return;
-        } else if (page == this.attempt.currentpage && !this.showSummary && slot !== undefined) {
+        } else if (page === this.attempt.currentpage && !this.showSummary && slot !== undefined) {
             // Navigating to a question in the current page.
             await this.scrollToQuestion(slot);
 
             return;
         } else if (
-            (page == this.attempt.currentpage && !this.showSummary) ||
-            (fromModal && this.isSequential && page != this.attempt.currentpage && page !== this.nextPage)
+            (page === this.attempt.currentpage && !this.showSummary) ||
+            (fromModal && this.isSequential && page !== this.attempt.currentpage && page !== this.nextPage)
         ) {
             // If the user is navigating to the current page we do nothing.
             // Also, in sequential quizzes we can only navigate to the current page.
@@ -344,8 +341,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
 
     /**
      * Convenience function to get the quiz data.
-     *
-     * @returns Promise resolved when done.
      */
     protected async fetchData(): Promise<void> {
         this.quiz = await AddonModQuiz.getQuiz(this.courseId, this.cmId);
@@ -403,7 +398,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
      *
      * @param userFinish Whether the user clicked to finish the attempt.
      * @param timeUp Whether the quiz time is up.
-     * @returns Promise resolved when done.
      */
     async finishAttempt(userFinish?: boolean, timeUp?: boolean): Promise<void> {
         if (!this.quiz || !this.attempt) {
@@ -417,7 +411,7 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
             if (!timeUp && this.attempt.state === AddonModQuizAttemptStates.IN_PROGRESS) {
                 let message = Translate.instant('addon.mod_quiz.confirmclose');
 
-                const unansweredCount = this.summaryQuestions
+                const unansweredCount = this.attemptSummary
                     .filter(question => AddonModQuiz.isQuestionUnanswered(question))
                     .length;
 
@@ -490,8 +484,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
 
     /**
      * Fix sequence checks of current page.
-     *
-     * @returns Promise resolved when done.
      */
     protected async fixSequenceChecks(): Promise<void> {
         if (!this.attempt) {
@@ -561,7 +553,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
      * Load a page questions.
      *
      * @param page The page to load.
-     * @returns Promise resolved when done.
      */
     protected async loadPage(page: number): Promise<void> {
         if (!this.quiz || !this.attempt) {
@@ -668,8 +659,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
 
     /**
      * Load attempt summary.
-     *
-     * @returns Promise resolved when done.
      */
     protected async loadSummary(): Promise<void> {
         if (!this.quiz || !this.attempt) {
@@ -682,21 +671,11 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
             this.partialCorrectIcon = CoreQuestionHelper.getPartiallyCorrectIcon().fullName;
         }
 
-        this.summaryQuestions = [];
-
-        this.summaryQuestions = await AddonModQuiz.getAttemptSummary(this.attempt.id, this.preflightData, {
-            cmId: this.quiz.coursemodule,
-            loadLocal: this.offline,
-            readingStrategy: this.offline ? CoreSitesReadingStrategy.PREFER_CACHE : CoreSitesReadingStrategy.ONLY_NETWORK,
-        });
-
-        this.summaryQuestions.forEach((question) => {
-            CoreQuestionHelper.populateQuestionStateClass(question);
-        });
+        await this.loadAttemptSummary();
 
         this.showSummary = true;
         this.canReturn = this.attempt.state === AddonModQuizAttemptStates.IN_PROGRESS && !this.attempt.finishedOffline;
-        this.preventSubmitMessages = AddonModQuiz.getPreventSubmitMessages(this.summaryQuestions);
+        this.preventSubmitMessages = AddonModQuiz.getPreventSubmitMessages(this.attemptSummary);
 
         this.dueDateWarning = AddonModQuiz.getAttemptDueDateWarning(this.quiz, this.attempt);
 
@@ -704,31 +683,27 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
     }
 
     /**
-     * Load data to navigate the questions using the navigation modal.
-     *
-     * @returns Promise resolved when done.
+     * Load attempt summary data.
      */
-    protected async loadNavigation(): Promise<void> {
-        if (!this.attempt) {
+    protected async loadAttemptSummary(): Promise<void> {
+        if (!this.quiz || !this.attempt) {
             return;
         }
 
         // We use the attempt summary to build the navigation because it contains all the questions.
-        this.navigation = await AddonModQuiz.getAttemptSummary(this.attempt.id, this.preflightData, {
-            cmId: this.quiz?.coursemodule,
+        this.attemptSummary = await AddonModQuiz.getAttemptSummary(this.attempt.id, this.preflightData, {
+            cmId: this.quiz.coursemodule,
             loadLocal: this.offline,
             readingStrategy: this.offline ? CoreSitesReadingStrategy.PREFER_CACHE : CoreSitesReadingStrategy.ONLY_NETWORK,
         });
 
-        this.navigation.forEach((question) => {
+        this.attemptSummary.forEach((question) => {
             CoreQuestionHelper.populateQuestionStateClass(question);
         });
     }
 
     /**
      * Open the navigation modal.
-     *
-     * @returns Promise resolved when done.
      */
     async openNavigation(): Promise<void> {
 
@@ -736,7 +711,7 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
             // Some data has changed, reload the navigation.
             const modal = await CoreLoadings.show();
 
-            await CorePromiseUtils.ignoreErrors(this.loadNavigation());
+            await CorePromiseUtils.ignoreErrors(this.loadAttemptSummary());
 
             modal.dismiss();
             this.reloadNavigation = false;
@@ -748,7 +723,7 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
         const modalData = await CoreModals.openSideModal<AddonModQuizNavigationModalReturn>({
             component: AddonModQuizNavigationModalComponent,
             componentProps: {
-                navigation: this.navigation,
+                navigation: this.attemptSummary,
                 summaryShown: this.showSummary,
                 currentPage: this.attempt?.currentpage,
                 nextPage: this.nextPage,
@@ -786,7 +761,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
      * @param userFinish Whether the user clicked to finish the attempt.
      * @param timeUp Whether the quiz time is up.
      * @param retrying Whether we're retrying the change.
-     * @returns Promise resolved when done.
      */
     protected async processAttempt(userFinish?: boolean, timeUp?: boolean, retrying?: boolean): Promise<void> {
         if (!this.quiz || !this.attempt) {
@@ -829,7 +803,9 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
             }
 
             // Sequence checks updated, try to send the data again.
-            return this.processAttempt(userFinish, timeUp, true);
+            await this.processAttempt(userFinish, timeUp, true);
+
+            return;
         }
 
         // Answers saved, cancel auto save.
@@ -840,7 +816,7 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
             CoreForms.triggerFormSubmittedEvent(this.formElement, !this.offline, CoreSites.getCurrentSiteId());
         }
 
-        return CoreQuestionHelper.clearTmpData(this.questions, this.component, this.quiz.coursemodule);
+        await CoreQuestionHelper.clearTmpData(this.questions, this.component, this.quiz.coursemodule);
     }
 
     /**
@@ -891,8 +867,6 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
 
     /**
      * Start or continue an attempt.
-     *
-     * @returns Promise resolved when done.
      */
     protected async startOrContinueAttempt(): Promise<void> {
         if (!this.quiz || !this.quizAccessInfo) {
@@ -922,7 +896,7 @@ export class AddonModQuizPlayerPage implements OnInit, OnDestroy, CanLeave {
 
         this.attempt = attempt;
 
-        await this.loadNavigation();
+        await this.loadAttemptSummary();
 
         if (this.attempt.state !== AddonModQuizAttemptStates.OVERDUE && !this.attempt.finishedOffline) {
             // Attempt not overdue and not finished in offline, load page.
diff --git a/src/addons/mod/quiz/pages/review/review.html b/src/addons/mod/quiz/pages/review/review.html
index 65a6d4904aa..aec5aeaf682 100644
--- a/src/addons/mod/quiz/pages/review/review.html
+++ b/src/addons/mod/quiz/pages/review/review.html
@@ -10,7 +10,7 @@ <h1>{{ 'addon.mod_quiz.review' | translate }}</h1>
         <ion-buttons slot="end">
             <ion-button fill="clear" *ngIf="navigation.length" [ariaLabel]="'addon.mod_quiz.opentoc' | translate" (click)="openNavigation()"
                 aria-haspopup="true">
-                <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
             </ion-button>
         </ion-buttons>
     </ion-toolbar>
diff --git a/src/addons/mod/quiz/pages/review/review.ts b/src/addons/mod/quiz/pages/review/review.ts
index 82124e21150..44276641630 100644
--- a/src/addons/mod/quiz/pages/review/review.ts
+++ b/src/addons/mod/quiz/pages/review/review.ts
@@ -144,8 +144,6 @@ export class AddonModQuizReviewPage implements OnInit {
 
     /**
      * Convenience function to get the quiz data.
-     *
-     * @returns Promise resolved when done.
      */
     protected async fetchData(): Promise<void> {
         try {
@@ -171,7 +169,6 @@ export class AddonModQuizReviewPage implements OnInit {
      * Load a page questions.
      *
      * @param page The page to load.
-     * @returns Promise resolved when done.
      */
     protected async loadPage(page: number): Promise<void> {
         if (!this.quiz) {
@@ -200,8 +197,6 @@ export class AddonModQuizReviewPage implements OnInit {
 
     /**
      * Load data to navigate the questions using the navigation modal.
-     *
-     * @returns Promise resolved when done.
      */
     protected async loadNavigation(): Promise<void> {
         // Get all questions in single page to retrieve all the questions.
diff --git a/src/addons/mod/quiz/services/access-rules-delegate.ts b/src/addons/mod/quiz/services/access-rules-delegate.ts
index 40b5f0c0155..e15ed792ac4 100644
--- a/src/addons/mod/quiz/services/access-rules-delegate.ts
+++ b/src/addons/mod/quiz/services/access-rules-delegate.ts
@@ -256,7 +256,6 @@ export class AddonModQuizAccessRuleDelegateService extends CoreDelegate<AddonMod
      * @param preflightData Preflight data gathered.
      * @param prefetch Whether the user is prefetching the quiz.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async notifyPreflightCheckPassed(
         rules: string[],
@@ -286,7 +285,6 @@ export class AddonModQuizAccessRuleDelegateService extends CoreDelegate<AddonMod
      * @param preflightData Preflight data gathered.
      * @param prefetch Whether the user is prefetching the quiz.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async notifyPreflightCheckFailed(
         rules: string[],
diff --git a/src/addons/mod/quiz/services/handlers/prefetch.ts b/src/addons/mod/quiz/services/handlers/prefetch.ts
index bb51503b24e..d2bad914304 100644
--- a/src/addons/mod/quiz/services/handlers/prefetch.ts
+++ b/src/addons/mod/quiz/services/handlers/prefetch.ts
@@ -248,23 +248,14 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
     }
 
     /**
-     * Whether or not the handler is enabled on a site level.
-     *
-     * @returns A boolean, or a promise resolved with a boolean, indicating if the handler is enabled.
+     * @inheritdoc
      */
     async isEnabled(): Promise<boolean> {
         return true;
     }
 
     /**
-     * Prefetch a module.
-     *
-     * @param module Module.
-     * @param courseId Course ID the module belongs to.
-     * @param single True if we're downloading a single module, false if we're downloading a whole section.
-     * @param dirPath Path of the directory where to store all the content files.
-     * @param canStart If true, start a new attempt if needed.
-     * @returns Promise resolved when done.
+     * @inheritdoc
      */
     async prefetch(
         module: SyncedModule,
@@ -292,7 +283,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param single True if we're downloading a single module, false if we're downloading a whole section.
      * @param canStart If true, start a new attempt if needed.
      * @param siteId Site ID.
-     * @returns Promise resolved when done.
      */
     protected async prefetchQuiz(
         module: CoreCourseAnyModuleData,
@@ -474,7 +464,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param accessInfo Quiz access info.
      * @param attempt Attempt.
      * @param modOptions Other options.
-     * @returns Promise resolved when done.
      */
     protected async prefetchAttemptReview(
         quiz: AddonModQuizQuizWSData,
@@ -511,7 +500,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param quiz Quiz.
      * @param attempt Attempt.
      * @param modOptions Other options.
-     * @returns Promise resolved when done.
      */
     protected async prefetchAttemptReviewFiles(
         quiz: AddonModQuizQuizWSData,
@@ -545,7 +533,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param quiz Quiz.
      * @param modOptions Other options.
      * @param siteId Site ID.
-     * @returns Promise resolved when done.
      */
     protected async prefetchGradeAndFeedback(
         quiz: AddonModQuizQuizWSData,
@@ -570,7 +557,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param quiz Quiz.
      * @param askPreflight Whether it should ask for preflight data if needed.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async prefetchQuizAndLastAttempt(quiz: AddonModQuizQuizWSData, askPreflight?: boolean, siteId?: string): Promise<void> {
         siteId = siteId || CoreSites.getCurrentSiteId();
@@ -617,7 +603,6 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      *
      * @param quiz Quiz.
      * @param options Other options.
-     * @returns Promise resolved when done.
      */
     async setStatusAfterPrefetch(
         quiz: AddonModQuizQuizWSData,
@@ -654,7 +639,7 @@ export class AddonModQuizPrefetchHandlerService extends CoreCourseActivityPrefet
      * @param module Module.
      * @param courseId Course ID the module belongs to
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
+     * @returns Sync results.
      */
     async sync(module: SyncedModule, courseId: number, siteId?: string): Promise<AddonModQuizSyncResult | undefined> {
         const quiz = await AddonModQuiz.getQuiz(courseId, module.id, { siteId });
diff --git a/src/addons/mod/quiz/services/handlers/push-click.ts b/src/addons/mod/quiz/services/handlers/push-click.ts
index 0b627910673..bc2aade7756 100644
--- a/src/addons/mod/quiz/services/handlers/push-click.ts
+++ b/src/addons/mod/quiz/services/handlers/push-click.ts
@@ -39,10 +39,7 @@ export class AddonModQuizPushClickHandlerService implements CorePushNotification
     protected readonly SUPPORTED_NAMES = ['submission', 'confirmation', 'attempt_overdue'];
 
     /**
-     * Check if a notification click is handled by this handler.
-     *
-     * @param notification The notification to check.
-     * @returns Whether the notification click is handled by this handler
+     * @inheritdoc
      */
     async handles(notification: AddonModQuizPushNotificationData): Promise<boolean> {
         return CoreUtils.isTrueOrOne(notification.notif) && notification.moodlecomponent == 'mod_quiz' &&
@@ -51,10 +48,7 @@ export class AddonModQuizPushClickHandlerService implements CorePushNotification
     }
 
     /**
-     * Handle the notification click.
-     *
-     * @param notification The notification to check.
-     * @returns Promise resolved when done.
+     * @inheritdoc
      */
     async handleClick(notification: AddonModQuizPushNotificationData): Promise<void> {
         const contextUrlParams = CoreUrl.extractUrlParams(notification.contexturl || '');
@@ -68,12 +62,14 @@ export class AddonModQuizPushClickHandlerService implements CorePushNotification
             contextUrlParams.page !== undefined
         ) {
             // A student made a submission, go to view the attempt.
-            return AddonModQuizHelper.handleReviewLink(
+            await AddonModQuizHelper.handleReviewLink(
                 Number(contextUrlParams.attempt),
                 Number(contextUrlParams.page),
                 Number(data.instance),
                 notification.site,
             );
+
+            return;
         }
 
         // Open the activity.
@@ -84,7 +80,7 @@ export class AddonModQuizPushClickHandlerService implements CorePushNotification
 
         await CorePromiseUtils.ignoreErrors(AddonModQuiz.invalidateContent(moduleId, courseId, notification.site));
 
-        return CoreCourseHelper.navigateToModule(moduleId, {
+        await CoreCourseHelper.navigateToModule(moduleId, {
             courseId,
             siteId: notification.site,
         });
diff --git a/src/addons/mod/quiz/services/handlers/sync-cron.ts b/src/addons/mod/quiz/services/handlers/sync-cron.ts
index db8ef878edb..1421a9a2766 100644
--- a/src/addons/mod/quiz/services/handlers/sync-cron.ts
+++ b/src/addons/mod/quiz/services/handlers/sync-cron.ts
@@ -27,21 +27,14 @@ export class AddonModQuizSyncCronHandlerService implements CoreCronHandler {
     name = 'AddonModQuizSyncCronHandler';
 
     /**
-     * Execute the process.
-     * Receives the ID of the site affected, undefined for all sites.
-     *
-     * @param siteId ID of the site affected, undefined for all sites.
-     * @param force Wether the execution is forced (manual sync).
-     * @returns Promise resolved when done, rejected if failure.
+     * @inheritdoc
      */
     execute(siteId?: string, force?: boolean): Promise<void> {
         return AddonModQuizSync.syncAllQuizzes(siteId, force);
     }
 
     /**
-     * Get the time between consecutive executions.
-     *
-     * @returns Time between consecutive executions (in ms).
+     * @inheritdoc
      */
     getInterval(): number {
         return AddonModQuizSync.syncInterval;
diff --git a/src/addons/mod/quiz/services/quiz-helper.ts b/src/addons/mod/quiz/services/quiz-helper.ts
index 85ba4d5053f..7c616624f28 100644
--- a/src/addons/mod/quiz/services/quiz-helper.ts
+++ b/src/addons/mod/quiz/services/quiz-helper.ts
@@ -334,7 +334,6 @@ export class AddonModQuizHelperProvider {
      * @param page Page to load, -1 to all questions in same page.
      * @param quizId Quiz ID.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async handleReviewLink(attemptId: number, page?: number, quizId?: number, siteId?: string): Promise<void> {
         siteId = siteId || CoreSites.getCurrentSiteId();
diff --git a/src/addons/mod/quiz/services/quiz-offline.ts b/src/addons/mod/quiz/services/quiz-offline.ts
index ff98e646a65..58bf97e7997 100644
--- a/src/addons/mod/quiz/services/quiz-offline.ts
+++ b/src/addons/mod/quiz/services/quiz-offline.ts
@@ -140,7 +140,7 @@ export class AddonModQuizOfflineProvider {
      * @param attemptId Attempt ID.
      * @param questions List of questions.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
+     * @returns Questions with local states loaded.
      */
     async loadQuestionsLocalStates(
         attemptId: number,
@@ -223,7 +223,6 @@ export class AddonModQuizOfflineProvider {
      *
      * @param attemptId Attempt ID.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async removeAttemptAndAnswers(attemptId: number, siteId?: string): Promise<void> {
         siteId = siteId || CoreSites.getCurrentSiteId();
@@ -263,7 +262,6 @@ export class AddonModQuizOfflineProvider {
      * @param answers Answers to save.
      * @param timeMod Time modified to set in the answers. If not defined, current time.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     async saveAnswers(
         quiz: AddonModQuizQuizWSData,
diff --git a/src/addons/mod/quiz/services/quiz-sync.ts b/src/addons/mod/quiz/services/quiz-sync.ts
index 400dedbaa28..f348ad1ab77 100644
--- a/src/addons/mod/quiz/services/quiz-sync.ts
+++ b/src/addons/mod/quiz/services/quiz-sync.ts
@@ -139,7 +139,6 @@ export class AddonModQuizSyncProvider extends CoreCourseActivitySyncBaseProvider
      * @param quiz Quiz.
      * @param courseId Course ID.
      * @param siteId Site ID. If not defined, current site.
-     * @returns Promise resolved when done.
      */
     protected async prefetchAfterUpdateQuiz(
         module: CoreCourseModuleBasicInfo,
@@ -187,7 +186,6 @@ export class AddonModQuizSyncProvider extends CoreCourseActivitySyncBaseProvider
      *
      * @param force Wether to force sync not depending on last execution.
      * @param siteId Site ID to sync.
-     * @returns Promise resolved if sync is successful, rejected if sync fails.
      */
     protected async syncAllQuizzesFunc(force: boolean, siteId: string): Promise<void> {
         // Get all offline attempts.
diff --git a/src/addons/mod/quiz/services/quiz.ts b/src/addons/mod/quiz/services/quiz.ts
index 938081dbb52..0272fa7b036 100644
--- a/src/addons/mod/quiz/services/quiz.ts
+++ b/src/addons/mod/quiz/services/quiz.ts
@@ -50,6 +50,7 @@ import {
     AddonModQuizGradeMethods,
     AddonModQuizDisplayOptionsAttemptStates,
     ADDON_MOD_QUIZ_IMMEDIATELY_AFTER_PERIOD,
+    AddonModQuizNavMethods,
 } from '../constants';
 import { CoreIonicColorNames } from '@singletons/colors';
 import { CoreCacheUpdateFrequency } from '@/core/constants';
@@ -1577,7 +1578,7 @@ export class AddonModQuizProvider {
      * @returns Whether navigation is sequential.
      */
     isNavigationSequential(quiz: AddonModQuizQuizWSData): boolean {
-        return quiz.navmethod == 'sequential';
+        return quiz.navmethod === AddonModQuizNavMethods.SEQ;
     }
 
     /**
@@ -2286,7 +2287,7 @@ export type AddonModQuizQuizWSData = {
     reviewrightanswer?: number; // Whether users are allowed to review their quiz attempts at various times.
     reviewoverallfeedback?: number; // Whether users are allowed to review their quiz attempts at various times.
     questionsperpage?: number; // How often to insert a page break when editing the quiz, or when shuffling the question order.
-    navmethod?: string; // Any constraints on how the user is allowed to navigate around the quiz.
+    navmethod?: AddonModQuizNavMethods; // Any constraints on how the user is allowed to navigate around the quiz.
     shuffleanswers?: number; // Whether the parts of the question should be shuffled, in those question types that support it.
     sumgrades?: number | null; // The total of all the question instance maxmarks.
     grade?: number; // The total that the quiz overall grade is scaled to be out of.
diff --git a/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_27.png b/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_27.png
index 46c03674485..48e9e920d8d 100644
Binary files a/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_27.png and b/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_27.png differ
diff --git a/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_42.png b/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_42.png
index e62984bde1d..88010fb8461 100644
Binary files a/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_42.png and b/src/addons/mod/quiz/tests/behat/snapshots/attempt-a-quiz-in-app-submit-a-quiz--review-a-quiz-attempt_42.png differ
diff --git a/src/addons/mod/scorm/pages/player/player.html b/src/addons/mod/scorm/pages/player/player.html
index ba56e50d795..8ecff8877d0 100644
--- a/src/addons/mod/scorm/pages/player/player.html
+++ b/src/addons/mod/scorm/pages/player/player.html
@@ -12,7 +12,7 @@ <h1>
             <core-button-with-spinner *ngIf="showToc" [loading]="loadingToc">
                 <ion-button fill="clear" *ngIf="toc.length" (click)="openToc()" [ariaLabel]="'addon.mod_scorm.toc' | translate"
                     aria-haspopup="true">
-                    <ion-icon name="fas-bookmark" slot="icon-only" aria-hidden="true" />
+                    <ion-icon name="fas-list-ul" slot="icon-only" aria-hidden="true" />
                 </ion-button>
             </core-button-with-spinner>
         </ion-buttons>
diff --git a/src/addons/qbehaviour/deferredcbm/services/handlers/deferredcbm.ts b/src/addons/qbehaviour/deferredcbm/services/handlers/deferredcbm.ts
index f7eabd3ea02..03337eb1447 100644
--- a/src/addons/qbehaviour/deferredcbm/services/handlers/deferredcbm.ts
+++ b/src/addons/qbehaviour/deferredcbm/services/handlers/deferredcbm.ts
@@ -21,6 +21,7 @@ import { CoreQuestionQuestionParsed, CoreQuestionsAnswers, CoreQuestionState } f
 import { CoreQuestionHelper } from '@features/question/services/question-helper';
 import { AddonQbehaviourDeferredCBMComponent } from '../../component/deferredcbm';
 import { CoreQuestionDelegate } from '@features/question/services/question-delegate';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support deferred CBM question behaviour.
@@ -89,12 +90,12 @@ export class AddonQbehaviourDeferredCBMHandlerService implements CoreQuestionBeh
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // First check if the question answer is complete.
         const complete = CoreQuestionDelegate.isCompleteResponse(question, answers, component, componentId);
         if (complete > 0) {
             // Answer is complete, check the user answered CBM too.
-            return answers['-certainty'] ? 1 : 0;
+            return answers['-certainty'] ? QuestionCompleteGradableResponse.YES : QuestionCompleteGradableResponse.NO;
         }
 
         return complete;
diff --git a/src/addons/qbehaviour/deferredfeedback/services/handlers/deferredfeedback.ts b/src/addons/qbehaviour/deferredfeedback/services/handlers/deferredfeedback.ts
index c0cc4ab2364..477f1804673 100644
--- a/src/addons/qbehaviour/deferredfeedback/services/handlers/deferredfeedback.ts
+++ b/src/addons/qbehaviour/deferredfeedback/services/handlers/deferredfeedback.ts
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import { Injectable } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestionBehaviourHandler, CoreQuestionQuestionWithAnswers } from '@features/question/services/behaviour-delegate';
 import { CoreQuestionDBRecord } from '@features/question/services/database/question';
@@ -134,7 +135,7 @@ export class AddonQbehaviourDeferredFeedbackHandlerService implements CoreQuesti
         }
 
         // Answers have changed. Now check if the response is complete and calculate the new state.
-        let complete: number;
+        let complete: QuestionCompleteGradableResponse;
         let newState: string;
 
         if (isCompleteFn) {
@@ -190,7 +191,7 @@ export type isCompleteResponseFunction = (
     answers: CoreQuestionsAnswers,
     component: string,
     componentId: string | number,
-) => number;
+) => QuestionCompleteGradableResponse;
 
 /**
  * Check if two responses are the same.
diff --git a/src/addons/qtype/calculated/calculated.module.ts b/src/addons/qtype/calculated/calculated.module.ts
index 73b7a5a3f76..75c77b89b92 100644
--- a/src/addons/qtype/calculated/calculated.module.ts
+++ b/src/addons/qtype/calculated/calculated.module.ts
@@ -14,18 +14,10 @@
 
 import { APP_INITIALIZER, NgModule } from '@angular/core';
 
-import { CoreSharedModule } from '@/core/shared.module';
 import { CoreQuestionDelegate } from '@features/question/services/question-delegate';
-import { AddonQtypeCalculatedComponent } from './component/calculated';
 import { AddonQtypeCalculatedHandler } from './services/handlers/calculated';
 
 @NgModule({
-    declarations: [
-        AddonQtypeCalculatedComponent,
-    ],
-    imports: [
-        CoreSharedModule,
-    ],
     providers: [
         {
             provide: APP_INITIALIZER,
@@ -35,8 +27,5 @@ import { AddonQtypeCalculatedHandler } from './services/handlers/calculated';
             },
         },
     ],
-    exports: [
-        AddonQtypeCalculatedComponent,
-    ],
 })
 export class AddonQtypeCalculatedModule {}
diff --git a/src/addons/qtype/calculated/services/handlers/calculated.ts b/src/addons/qtype/calculated/services/handlers/calculated.ts
index 316372f107f..aee236e113a 100644
--- a/src/addons/qtype/calculated/services/handlers/calculated.ts
+++ b/src/addons/qtype/calculated/services/handlers/calculated.ts
@@ -12,195 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Injectable, Type } from '@angular/core';
+import { Injectable } from '@angular/core';
+import { AddonQtypeNumericalHandlerService } from '@addons/qtype/numerical/services/handlers/numerical';
 
-import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
-import { CoreQuestionHandler } from '@features/question/services/question-delegate';
-import { convertTextToHTMLElement } from '@/core/utils/create-html-element';
-import { CoreObject } from '@singletons/object';
 import { makeSingleton } from '@singletons';
 
 /**
  * Handler to support calculated question type.
+ * This question type depends on numeric question type.
  */
 @Injectable({ providedIn: 'root' })
-export class AddonQtypeCalculatedHandlerService implements CoreQuestionHandler {
-
-    static readonly UNITINPUT = '0';
-    static readonly UNITRADIO = '1';
-    static readonly UNITSELECT = '2';
-    static readonly UNITNONE = '3';
-
-    static readonly UNITGRADED = '1';
-    static readonly UNITOPTIONAL = '0';
+export class AddonQtypeCalculatedHandlerService  extends AddonQtypeNumericalHandlerService {
 
     name = 'AddonQtypeCalculated';
     type = 'qtype_calculated';
 
-    /**
-     * @inheritdoc
-     */
-    async getComponent(): Promise<Type<unknown>> {
-        const { AddonQtypeCalculatedComponent } = await import('../../component/calculated');
-
-        return AddonQtypeCalculatedComponent;
-    }
-
-    /**
-     * Check if the units are in a separate field for the question.
-     *
-     * @param question Question.
-     * @returns Whether units are in a separate field.
-     */
-    hasSeparateUnitField(question: CoreQuestionQuestionParsed): boolean {
-        if (!question.parsedSettings) {
-            const element = convertTextToHTMLElement(question.html);
-
-            return !!(element.querySelector('select[name*=unit]') || element.querySelector('input[type="radio"]'));
-        }
-
-        return question.parsedSettings.unitdisplay === AddonQtypeCalculatedHandlerService.UNITRADIO ||
-            question.parsedSettings.unitdisplay === AddonQtypeCalculatedHandlerService.UNITSELECT;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isCompleteResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        if (!this.isGradableResponse(question, answers)) {
-            return 0;
-        }
-
-        const { answer, unit } = this.parseAnswer(question, <string> answers.answer);
-        if (answer === null) {
-            return 0;
-        }
-
-        if (!question.parsedSettings) {
-            if (this.hasSeparateUnitField(question)) {
-                return this.isValidValue(<string> answers.unit) ? 1 : 0;
-            }
-
-            // We cannot know if the answer should contain units or not.
-            return -1;
-        }
-
-        if (question.parsedSettings.unitdisplay != AddonQtypeCalculatedHandlerService.UNITINPUT && unit) {
-            // There should be no units or be outside of the input, not valid.
-            return 0;
-        }
-
-        if (this.hasSeparateUnitField(question) && !this.isValidValue(<string> answers.unit)) {
-            // Unit not supplied as a separate field and it's required.
-            return 0;
-        }
-
-        if (question.parsedSettings.unitdisplay == AddonQtypeCalculatedHandlerService.UNITINPUT &&
-                question.parsedSettings.unitgradingtype == AddonQtypeCalculatedHandlerService.UNITGRADED &&
-                !this.isValidValue(unit)) {
-            // Unit not supplied inside the input and it's required.
-            return 0;
-        }
-
-        return 1;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    async isEnabled(): Promise<boolean> {
-        return true;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isGradableResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        return this.isValidValue(<string> answers.answer) ? 1 : 0;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isSameResponse(
-        question: CoreQuestionQuestionParsed,
-        prevAnswers: CoreQuestionsAnswers,
-        newAnswers: CoreQuestionsAnswers,
-    ): boolean {
-        return CoreObject.sameAtKeyMissingIsBlank(prevAnswers, newAnswers, 'answer') &&
-            CoreObject.sameAtKeyMissingIsBlank(prevAnswers, newAnswers, 'unit');
-    }
-
-    /**
-     * Check if a value is valid (not empty).
-     *
-     * @param value Value to check.
-     * @returns Whether the value is valid.
-     */
-    isValidValue(value: string | number | null): boolean {
-        return !!value || value === '0' || value === 0;
-    }
-
-    /**
-     * Parse an answer string.
-     *
-     * @param question Question.
-     * @param answer Answer.
-     * @returns Answer and unit.
-     */
-    parseAnswer(question: CoreQuestionQuestionParsed, answer: string): { answer: number | null; unit: string | null } {
-        if (!answer) {
-            return { answer: null, unit: null };
-        }
-
-        let regexString = '[+-]?(?:\\d+(?:\\.\\d*)?|\\.\\d+)(?:e[-+]?\\d+)?';
-
-        // Strip spaces (which may be thousands separators) and change other forms of writing e to e.
-        answer = answer.replace(/ /g, '');
-        answer = answer.replace(/(?:e|E|(?:x|\*|×)10(?:\^|\*\*))([+-]?\d+)/, 'e$1');
-
-        // If a '.' is present or there are multiple ',' (i.e. 2,456,789) assume ',' is a thousands separator and strip it.
-        // Else assume it is a decimal separator, and change it to '.'.
-        if (answer.indexOf('.') != -1 || answer.split(',').length - 1 > 1) {
-            answer = answer.replace(',', '');
-        } else {
-            answer = answer.replace(',', '.');
-        }
-
-        let unitsLeft = false;
-        let match: RegExpMatchArray | null = null;
-
-        if (!question.parsedSettings || question.parsedSettings.unitsleft === null) {
-            // We don't know if units should be before or after so we check both.
-            match = answer.match(new RegExp('^' + regexString));
-            if (!match) {
-                unitsLeft = true;
-                match = answer.match(new RegExp(regexString + '$'));
-            }
-        } else {
-            unitsLeft = question.parsedSettings.unitsleft == '1';
-            regexString = unitsLeft ? regexString + '$' : '^' + regexString;
-
-            match = answer.match(new RegExp(regexString));
-        }
-
-        if (!match) {
-            return { answer: null, unit: null };
-        }
-
-        const numberString = match[0];
-        const unit = unitsLeft ? answer.substring(0, answer.length - match[0].length) : answer.substring(match[0].length);
-
-        // No need to calculate the multiplier.
-        return { answer: Number(numberString), unit };
-    }
-
 }
 
 export const AddonQtypeCalculatedHandler = makeSingleton(AddonQtypeCalculatedHandlerService);
diff --git a/src/addons/qtype/calculatedmulti/services/handlers/calculatedmulti.ts b/src/addons/qtype/calculatedmulti/services/handlers/calculatedmulti.ts
index 3d06667c31f..f436f232906 100644
--- a/src/addons/qtype/calculatedmulti/services/handlers/calculatedmulti.ts
+++ b/src/addons/qtype/calculatedmulti/services/handlers/calculatedmulti.ts
@@ -18,6 +18,7 @@ import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/ques
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { makeSingleton } from '@singletons';
 import { AddonQtypeMultichoiceHandler } from '@addons/qtype/multichoice/services/handlers/multichoice';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support calculated multi question type.
@@ -44,7 +45,7 @@ export class AddonQtypeCalculatedMultiHandlerService implements CoreQuestionHand
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // This question type depends on multichoice.
         return AddonQtypeMultichoiceHandler.isCompleteResponseSingle(answers);
     }
@@ -62,7 +63,7 @@ export class AddonQtypeCalculatedMultiHandlerService implements CoreQuestionHand
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // This question type depends on multichoice.
         return AddonQtypeMultichoiceHandler.isGradableResponseSingle(answers);
     }
@@ -79,6 +80,16 @@ export class AddonQtypeCalculatedMultiHandlerService implements CoreQuestionHand
         return AddonQtypeMultichoiceHandler.isSameResponseSingle(prevAnswers, newAnswers);
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        return AddonQtypeMultichoiceHandler.getValidationError(question, answers);
+    }
+
 }
 
 export const AddonQtypeCalculatedMultiHandler = makeSingleton(AddonQtypeCalculatedMultiHandlerService);
diff --git a/src/addons/qtype/calculatedsimple/services/handlers/calculatedsimple.ts b/src/addons/qtype/calculatedsimple/services/handlers/calculatedsimple.ts
index 787e2d552cf..c7cc17de447 100644
--- a/src/addons/qtype/calculatedsimple/services/handlers/calculatedsimple.ts
+++ b/src/addons/qtype/calculatedsimple/services/handlers/calculatedsimple.ts
@@ -12,73 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Injectable, Type } from '@angular/core';
+import { Injectable } from '@angular/core';
 
-import { CoreQuestionHandler } from '@features/question/services/question-delegate';
-import { AddonQtypeCalculatedHandler } from '@addons/qtype/calculated/services/handlers/calculated';
-import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { makeSingleton } from '@singletons';
+import { AddonQtypeNumericalHandlerService } from '@addons/qtype/numerical/services/handlers/numerical';
 
 /**
  * Handler to support calculated simple question type.
+ * This question type depends on numeric question type.
  */
 @Injectable({ providedIn: 'root' })
-export class AddonQtypeCalculatedSimpleHandlerService implements CoreQuestionHandler {
+export class AddonQtypeCalculatedSimpleHandlerService extends AddonQtypeNumericalHandlerService {
 
     name = 'AddonQtypeCalculatedSimple';
     type = 'qtype_calculatedsimple';
 
-    /**
-     * @inheritdoc
-     */
-    async getComponent(): Promise<Type<unknown>> {
-        // Calculated simple behaves like a calculated, use the same component.
-        const { AddonQtypeCalculatedComponent } = await import('@addons/qtype/calculated/component/calculated');
-
-        return AddonQtypeCalculatedComponent;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isCompleteResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        // This question type depends on calculated.
-        return AddonQtypeCalculatedHandler.isCompleteResponse(question, answers);
-    }
-
-    /**
-     * @inheritdoc
-     */
-    async isEnabled(): Promise<boolean> {
-        return true;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isGradableResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        // This question type depends on calculated.
-        return AddonQtypeCalculatedHandler.isGradableResponse(question, answers);
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isSameResponse(
-        question: CoreQuestionQuestionParsed,
-        prevAnswers: CoreQuestionsAnswers,
-        newAnswers: CoreQuestionsAnswers,
-    ): boolean {
-        // This question type depends on calculated.
-        return AddonQtypeCalculatedHandler.isSameResponse(question, prevAnswers, newAnswers);
-    }
-
 }
 
 export const AddonQtypeCalculatedSimpleHandler = makeSingleton(AddonQtypeCalculatedSimpleHandlerService);
diff --git a/src/addons/qtype/ddimageortext/component/ddimageortext.ts b/src/addons/qtype/ddimageortext/component/ddimageortext.ts
index 2fbf0b74689..3c1ffacaa2c 100644
--- a/src/addons/qtype/ddimageortext/component/ddimageortext.ts
+++ b/src/addons/qtype/ddimageortext/component/ddimageortext.ts
@@ -45,11 +45,15 @@ export class AddonQtypeDdImageOrTextComponent
      */
     init(): void {
         if (!this.question) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
         const questionElement = this.initComponent();
         if (!questionElement) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
@@ -57,6 +61,7 @@ export class AddonQtypeDdImageOrTextComponent
         const ddArea = questionElement.querySelector('.ddarea');
         if (!ddArea) {
             this.logger.warn('Aborting because of an error parsing question.', this.question.slot);
+            this.onReadyPromise.resolve();
 
             return CoreQuestionHelper.showComponentError(this.onAbort);
         }
@@ -84,6 +89,7 @@ export class AddonQtypeDdImageOrTextComponent
         }
 
         this.question.loaded = false;
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/ddimageortext/lang.json b/src/addons/qtype/ddimageortext/lang.json
new file mode 100644
index 00000000000..ca2e37d3604
--- /dev/null
+++ b/src/addons/qtype/ddimageortext/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleasedraganimagetoeachdropregion": "Your answer is not complete; please drag an item to each drop region."
+}
diff --git a/src/addons/qtype/ddimageortext/services/handlers/ddimageortext.ts b/src/addons/qtype/ddimageortext/services/handlers/ddimageortext.ts
index 5729a9fe05e..22f2be6416c 100644
--- a/src/addons/qtype/ddimageortext/services/handlers/ddimageortext.ts
+++ b/src/addons/qtype/ddimageortext/services/handlers/ddimageortext.ts
@@ -13,10 +13,11 @@
 // limitations under the License.
 
 import { Injectable, Type } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
 
 /**
  * Handler to support drag-and-drop onto image question type.
@@ -53,17 +54,17 @@ export class AddonQtypeDdImageOrTextHandlerService implements CoreQuestionHandle
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // An answer is complete if all drop zones have an answer.
         // We should always receive all the drop zones with their value ('' if not answered).
         for (const name in answers) {
             const value = answers[name];
             if (!value || value === '0') {
-                return 0;
+                return QuestionCompleteGradableResponse.NO;
             }
         }
 
-        return 1;
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
@@ -79,15 +80,15 @@ export class AddonQtypeDdImageOrTextHandlerService implements CoreQuestionHandle
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse{
         for (const name in answers) {
             const value = answers[name];
             if (value && value !== '0') {
-                return 1;
+                return QuestionCompleteGradableResponse.YES;
             }
         }
 
-        return 0;
+        return QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -101,6 +102,20 @@ export class AddonQtypeDdImageOrTextHandlerService implements CoreQuestionHandle
         return CoreQuestion.compareAllAnswers(prevAnswers, newAnswers);
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isCompleteResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_ddimageortext.pleasedraganimagetoeachdropregion');
+    }
+
 }
 
 export const AddonQtypeDdImageOrTextHandler = makeSingleton(AddonQtypeDdImageOrTextHandlerService);
diff --git a/src/addons/qtype/ddmarker/component/ddmarker.ts b/src/addons/qtype/ddmarker/component/ddmarker.ts
index e2cd2ebaa5e..a0026a62c5f 100644
--- a/src/addons/qtype/ddmarker/component/ddmarker.ts
+++ b/src/addons/qtype/ddmarker/component/ddmarker.ts
@@ -51,11 +51,15 @@ export class AddonQtypeDdMarkerComponent
      */
     init(): void {
         if (!this.question) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
         const questionElement = this.initComponent();
         if (!questionElement) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
@@ -65,6 +69,7 @@ export class AddonQtypeDdMarkerComponent
 
         if (!ddArea || !ddForm) {
             this.logger.warn('Aborting because of an error parsing question.', this.question.slot);
+            this.onReadyPromise.resolve();
 
             return CoreQuestionHelper.showComponentError(this.onAbort);
         }
@@ -107,6 +112,7 @@ export class AddonQtypeDdMarkerComponent
         }
 
         this.question.loaded = false;
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/ddmarker/lang.json b/src/addons/qtype/ddmarker/lang.json
new file mode 100644
index 00000000000..06cf17456d2
--- /dev/null
+++ b/src/addons/qtype/ddmarker/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleasedragatleastonemarker": "Your answer is not complete; you must place at least one marker on the image."
+}
diff --git a/src/addons/qtype/ddmarker/services/handlers/ddmarker.ts b/src/addons/qtype/ddmarker/services/handlers/ddmarker.ts
index 899e0619257..38754da8a62 100644
--- a/src/addons/qtype/ddmarker/services/handlers/ddmarker.ts
+++ b/src/addons/qtype/ddmarker/services/handlers/ddmarker.ts
@@ -13,12 +13,13 @@
 // limitations under the License.
 
 import { Injectable, Type } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { CoreQuestionHelper, CoreQuestionQuestion } from '@features/question/services/question-helper';
 import { CoreWSFile } from '@services/ws';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
 
 /**
  * Handler to support drag-and-drop markers question type.
@@ -55,15 +56,15 @@ export class AddonQtypeDdMarkerHandlerService implements CoreQuestionHandler {
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // If 1 dragitem is set we assume the answer is complete (like Moodle does).
         for (const name in answers) {
-            if (answers[name]) {
-                return 1;
+            if (name !== ':sequencecheck' && answers[name]) {
+                return QuestionCompleteGradableResponse.YES;
             }
         }
 
-        return 0;
+        return QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -79,7 +80,7 @@ export class AddonQtypeDdMarkerHandlerService implements CoreQuestionHandler {
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         return this.isCompleteResponse(question, answers);
     }
 
@@ -102,7 +103,7 @@ export class AddonQtypeDdMarkerHandlerService implements CoreQuestionHandler {
 
         CoreQuestionHelper.extractQuestionScripts(treatedQuestion, usageId);
 
-        if (treatedQuestion.amdArgs && typeof treatedQuestion.amdArgs[1] == 'string') {
+        if (treatedQuestion.amdArgs && typeof treatedQuestion.amdArgs[1] === 'string') {
             // Moodle 3.6+.
             return [{
                 fileurl: treatedQuestion.amdArgs[1],
@@ -112,6 +113,20 @@ export class AddonQtypeDdMarkerHandlerService implements CoreQuestionHandler {
         return [];
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isCompleteResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_ddmarker.pleasedragatleastonemarker');
+    }
+
 }
 
 export const AddonQtypeDdMarkerHandler = makeSingleton(AddonQtypeDdMarkerHandlerService);
diff --git a/src/addons/qtype/ddwtos/component/ddwtos.ts b/src/addons/qtype/ddwtos/component/ddwtos.ts
index eb9e11b5e73..fbf571eaca4 100644
--- a/src/addons/qtype/ddwtos/component/ddwtos.ts
+++ b/src/addons/qtype/ddwtos/component/ddwtos.ts
@@ -47,11 +47,15 @@ export class AddonQtypeDdwtosComponent extends CoreQuestionBaseComponent<AddonMo
      */
     init(): void {
         if (!this.question) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
         const questionElement = this.initComponent();
         if (!questionElement) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
@@ -65,6 +69,7 @@ export class AddonQtypeDdwtosComponent extends CoreQuestionBaseComponent<AddonMo
         const answerContainer = questionElement.querySelector('.answercontainer');
         if (!answerContainer) {
             this.logger.warn('Aborting because of an error parsing question.', this.question.slot);
+            this.onReadyPromise.resolve();
 
             return CoreQuestionHelper.showComponentError(this.onAbort);
         }
@@ -98,6 +103,7 @@ export class AddonQtypeDdwtosComponent extends CoreQuestionBaseComponent<AddonMo
         this.question.text = questionText;
 
         this.question.loaded = false;
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/ddwtos/services/handlers/ddwtos.ts b/src/addons/qtype/ddwtos/services/handlers/ddwtos.ts
index f6766968198..2295737a99e 100644
--- a/src/addons/qtype/ddwtos/services/handlers/ddwtos.ts
+++ b/src/addons/qtype/ddwtos/services/handlers/ddwtos.ts
@@ -12,32 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import { AddonQtypeGapSelectHandlerService } from '@addons/qtype/gapselect/services/handlers/gapselect';
 import { Injectable, Type } from '@angular/core';
 
-import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
-import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { makeSingleton } from '@singletons';
 
 /**
  * Handler to support drag-and-drop words into sentences question type.
+ * This question type is a variation of gapselect.
  */
 @Injectable({ providedIn: 'root' })
-export class AddonQtypeDdwtosHandlerService implements CoreQuestionHandler {
+export class AddonQtypeDdwtosHandlerService extends AddonQtypeGapSelectHandlerService {
 
     name = 'AddonQtypeDdwtos';
     type = 'qtype_ddwtos';
 
-    /**
-     * @inheritdoc
-     */
-    getBehaviour(question: CoreQuestionQuestionParsed, behaviour: string): string {
-        if (behaviour === 'interactive') {
-            return 'interactivecountback';
-        }
-
-        return behaviour;
-    }
-
     /**
      * @inheritdoc
      */
@@ -47,58 +36,6 @@ export class AddonQtypeDdwtosHandlerService implements CoreQuestionHandler {
         return AddonQtypeDdwtosComponent;
     }
 
-    /**
-     * @inheritdoc
-     */
-    isCompleteResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        for (const name in answers) {
-            const value = answers[name];
-            if (!value || value === '0') {
-                return 0;
-            }
-        }
-
-        return 1;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    async isEnabled(): Promise<boolean> {
-        return true;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isGradableResponse(
-        question: CoreQuestionQuestionParsed,
-        answers: CoreQuestionsAnswers,
-    ): number {
-        for (const name in answers) {
-            const value = answers[name];
-            if (value && value !== '0') {
-                return 1;
-            }
-        }
-
-        return 0;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    isSameResponse(
-        question: CoreQuestionQuestionParsed,
-        prevAnswers: CoreQuestionsAnswers,
-        newAnswers: CoreQuestionsAnswers,
-    ): boolean {
-        return CoreQuestion.compareAllAnswers(prevAnswers, newAnswers);
-    }
-
 }
 
 export const AddonQtypeDdwtosHandler = makeSingleton(AddonQtypeDdwtosHandlerService);
diff --git a/src/addons/qtype/description/component/description.ts b/src/addons/qtype/description/component/description.ts
index f57f77f7f73..c50f2d0655e 100644
--- a/src/addons/qtype/description/component/description.ts
+++ b/src/addons/qtype/description/component/description.ts
@@ -36,12 +36,16 @@ export class AddonQtypeDescriptionComponent extends CoreQuestionBaseComponent {
     init(): void {
         const questionEl = this.initComponent();
         if (!questionEl) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
         // Get the "seen" hidden input.
         const input = questionEl.querySelector<HTMLInputElement>('input[type="hidden"][name*=seen]');
         if (!input) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
diff --git a/src/addons/qtype/essay/component/essay.ts b/src/addons/qtype/essay/component/essay.ts
index 8859c226455..216c1b3bb89 100644
--- a/src/addons/qtype/essay/component/essay.ts
+++ b/src/addons/qtype/essay/component/essay.ts
@@ -45,6 +45,8 @@ export class AddonQtypeEssayComponent extends CoreQuestionBaseComponent<AddonMod
      */
     init(): void {
         if (!this.question) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
@@ -57,6 +59,7 @@ export class AddonQtypeEssayComponent extends CoreQuestionBaseComponent<AddonMod
         if (this.question?.allowsAttachments && this.uploadFilesSupported && !this.review) {
             this.loadAttachments();
         }
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/essay/services/handlers/essay.ts b/src/addons/qtype/essay/services/handlers/essay.ts
index 1ded4f9db73..64d62d75837 100644
--- a/src/addons/qtype/essay/services/handlers/essay.ts
+++ b/src/addons/qtype/essay/services/handlers/essay.ts
@@ -28,6 +28,7 @@ import { CoreObject } from '@singletons/object';
 import { CoreWSFile } from '@services/ws';
 import { makeSingleton, Translate } from '@singletons';
 import { CoreFileHelper } from '@services/file-helper';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support essay question type.
@@ -84,8 +85,8 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
     protected getAllowedOptions(question: CoreQuestionQuestionParsed): { text: boolean; attachments: boolean } {
         if (question.parsedSettings) {
             return {
-                text: question.parsedSettings.responseformat != 'noinline',
-                attachments: question.parsedSettings.attachments != '0',
+                text: question.parsedSettings.responseformat !== 'noinline',
+                attachments: question.parsedSettings.attachments !== '0',
             };
         }
 
@@ -137,6 +138,8 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
         onlineError: string | undefined,
+        component: string,
+        componentId: string | number,
     ): string | undefined {
         if (answers.answer === undefined) {
             // Not answered in offline.
@@ -148,6 +151,11 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
             return;
         }
 
+        // Continue check in case the response completion cannot be determined.
+        if (this.isCompleteResponse(question, answers, component, componentId) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
         return this.checkInputWordCount(question, <string> answers.answer, onlineError);
     }
 
@@ -195,34 +203,38 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number {
+    ):  QuestionCompleteGradableResponse {
 
         const hasTextAnswer = !!answers.answer;
         const uploadFilesSupported = question.responsefileareas !== undefined;
         const allowedOptions = this.getAllowedOptions(question);
 
         if (hasTextAnswer && this.checkInputWordCount(question, <string> answers.answer, undefined)) {
-            return 0;
+            return QuestionCompleteGradableResponse.NO;
         }
 
         if (!allowedOptions.attachments) {
-            return hasTextAnswer ? 1 : 0;
+            return hasTextAnswer ? QuestionCompleteGradableResponse.YES : QuestionCompleteGradableResponse.NO;
         }
 
         if (!uploadFilesSupported || !question.parsedSettings) {
             // We can't know if the attachments are required or if the user added any in web.
-            return -1;
+            return QuestionCompleteGradableResponse.UNKNOWN;
         }
 
         const questionComponentId = CoreQuestion.getQuestionComponentId(question, componentId);
         const attachments = CoreFileSession.getFiles(component, questionComponentId);
 
         if (!allowedOptions.text) {
-            return attachments && attachments.length >= Number(question.parsedSettings.attachmentsrequired) ? 1 : 0;
+            return attachments && attachments.length >= Number(question.parsedSettings.attachmentsrequired)
+                ? QuestionCompleteGradableResponse.YES
+                : QuestionCompleteGradableResponse.NO;
         }
 
-        return ((hasTextAnswer || question.parsedSettings.responserequired == '0') &&
-                (attachments && attachments.length >= Number(question.parsedSettings.attachmentsrequired))) ? 1 : 0;
+        return ((hasTextAnswer || question.parsedSettings.responserequired === '0') &&
+                (attachments && attachments.length >= Number(question.parsedSettings.attachmentsrequired)))
+                    ? QuestionCompleteGradableResponse.YES
+                    : QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -240,16 +252,18 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         if (question.responsefileareas === undefined) {
-            return -1;
+            return QuestionCompleteGradableResponse.UNKNOWN;
         }
 
         const questionComponentId = CoreQuestion.getQuestionComponentId(question, componentId);
         const attachments = CoreFileSession.getFiles(component, questionComponentId);
 
         // Determine if the given response has online text or attachments.
-        return (answers.answer && answers.answer !== '') || (attachments && attachments.length > 0) ? 1 : 0;
+        return (answers.answer && answers.answer !== '') || (attachments && attachments.length > 0)
+            ? QuestionCompleteGradableResponse.YES
+            : QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -452,8 +466,8 @@ export class AddonQtypeEssayHandlerService implements CoreQuestionHandler {
         if (question.isPlainText !== undefined) {
             isPlainText = question.isPlainText;
         } else if (question.parsedSettings) {
-            isPlainText = question.parsedSettings.responseformat == 'monospaced' ||
-                question.parsedSettings.responseformat == 'plain';
+            isPlainText = question.parsedSettings.responseformat === 'monospaced' ||
+                question.parsedSettings.responseformat === 'plain';
         } else {
             const questionEl = convertTextToHTMLElement(question.html);
             isPlainText = !!questionEl.querySelector('.qtype_essay_monospaced') || !!questionEl.querySelector('.qtype_essay_plain');
diff --git a/src/addons/qtype/gapselect/component/gapselect.ts b/src/addons/qtype/gapselect/component/gapselect.ts
index 0c0852eb1f0..4b16d39661a 100644
--- a/src/addons/qtype/gapselect/component/gapselect.ts
+++ b/src/addons/qtype/gapselect/component/gapselect.ts
@@ -36,6 +36,7 @@ export class AddonQtypeGapSelectComponent extends CoreQuestionBaseComponent {
      */
     init(): void {
         this.initOriginalTextComponent('.qtext');
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/gapselect/lang.json b/src/addons/qtype/gapselect/lang.json
new file mode 100644
index 00000000000..cb8e3bed9df
--- /dev/null
+++ b/src/addons/qtype/gapselect/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleaseputananswerineachbox": "Please put an answer in each box."
+}
diff --git a/src/addons/qtype/gapselect/services/handlers/gapselect.ts b/src/addons/qtype/gapselect/services/handlers/gapselect.ts
index 3aa587ccd2c..bcb06a93f2c 100644
--- a/src/addons/qtype/gapselect/services/handlers/gapselect.ts
+++ b/src/addons/qtype/gapselect/services/handlers/gapselect.ts
@@ -13,10 +13,11 @@
 // limitations under the License.
 
 import { Injectable, Type } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
 
 /**
  * Handler to support gapselect question type.
@@ -53,16 +54,16 @@ export class AddonQtypeGapSelectHandlerService implements CoreQuestionHandler {
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // We should always get a value for each select so we can assume we receive all the possible answers.
         for (const name in answers) {
             const value = answers[name];
             if (!value || value === '0') {
-                return 0;
+                return QuestionCompleteGradableResponse.NO;
             }
         }
 
-        return 1;
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
@@ -78,16 +79,16 @@ export class AddonQtypeGapSelectHandlerService implements CoreQuestionHandler {
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // We should always get a value for each select so we can assume we receive all the possible answers.
         for (const name in answers) {
             const value = answers[name];
-            if (value) {
-                return 1;
+            if (value && value !== '0') {
+                return QuestionCompleteGradableResponse.YES;
             }
         }
 
-        return 0;
+        return QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -101,6 +102,20 @@ export class AddonQtypeGapSelectHandlerService implements CoreQuestionHandler {
         return CoreQuestion.compareAllAnswers(prevAnswers, newAnswers);
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isCompleteResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_gapselect.pleaseputananswerineachbox');
+    }
+
 }
 
 export const AddonQtypeGapSelectHandler = makeSingleton(AddonQtypeGapSelectHandlerService);
diff --git a/src/addons/qtype/match/component/match.ts b/src/addons/qtype/match/component/match.ts
index 7f0f5738395..98d6e383d42 100644
--- a/src/addons/qtype/match/component/match.ts
+++ b/src/addons/qtype/match/component/match.ts
@@ -35,6 +35,7 @@ export class AddonQtypeMatchComponent extends CoreQuestionBaseComponent<AddonMod
      */
     init(): void {
         this.initMatchComponent();
+        this.onReadyPromise.resolve();
     }
 
 }
diff --git a/src/addons/qtype/match/lang.json b/src/addons/qtype/match/lang.json
new file mode 100644
index 00000000000..fa277aacca7
--- /dev/null
+++ b/src/addons/qtype/match/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleaseananswerallparts": "Please answer all parts of the question."
+}
diff --git a/src/addons/qtype/match/services/handlers/match.ts b/src/addons/qtype/match/services/handlers/match.ts
index e70ef44fc70..88f64304507 100644
--- a/src/addons/qtype/match/services/handlers/match.ts
+++ b/src/addons/qtype/match/services/handlers/match.ts
@@ -13,10 +13,11 @@
 // limitations under the License.
 
 import { Injectable, Type } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
 
 /**
  * Handler to support match question type.
@@ -53,16 +54,16 @@ export class AddonQtypeMatchHandlerService implements CoreQuestionHandler {
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // We should always get a value for each select so we can assume we receive all the possible answers.
         for (const name in answers) {
             const value = answers[name];
             if (!value || value === '0') {
-                return 0;
+                return QuestionCompleteGradableResponse.NO;
             }
         }
 
-        return 1;
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
@@ -78,16 +79,16 @@ export class AddonQtypeMatchHandlerService implements CoreQuestionHandler {
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // We should always get a value for each select so we can assume we receive all the possible answers.
         for (const name in answers) {
             const value = answers[name];
             if (value && value !== '0') {
-                return 1;
+                return QuestionCompleteGradableResponse.YES;
             }
         }
 
-        return 0;
+        return QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -101,6 +102,20 @@ export class AddonQtypeMatchHandlerService implements CoreQuestionHandler {
         return CoreQuestion.compareAllAnswers(prevAnswers, newAnswers);
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isCompleteResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_match.pleaseananswerallparts');
+    }
+
 }
 
 export const AddonQtypeMatchHandler = makeSingleton(AddonQtypeMatchHandlerService);
diff --git a/src/addons/qtype/multianswer/component/multianswer.ts b/src/addons/qtype/multianswer/component/multianswer.ts
index f9c3adc3c13..22455477433 100644
--- a/src/addons/qtype/multianswer/component/multianswer.ts
+++ b/src/addons/qtype/multianswer/component/multianswer.ts
@@ -35,6 +35,7 @@ export class AddonQtypeMultiAnswerComponent extends CoreQuestionBaseComponent {
      */
     init(): void {
         this.initOriginalTextComponent('.formulation');
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/multianswer/lang.json b/src/addons/qtype/multianswer/lang.json
new file mode 100644
index 00000000000..fa277aacca7
--- /dev/null
+++ b/src/addons/qtype/multianswer/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleaseananswerallparts": "Please answer all parts of the question."
+}
diff --git a/src/addons/qtype/multianswer/services/handlers/multianswer.ts b/src/addons/qtype/multianswer/services/handlers/multianswer.ts
index 322c75d6954..8babbaa67b2 100644
--- a/src/addons/qtype/multianswer/services/handlers/multianswer.ts
+++ b/src/addons/qtype/multianswer/services/handlers/multianswer.ts
@@ -13,11 +13,12 @@
 // limitations under the License.
 
 import { Injectable, Type } from '@angular/core';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { CoreQuestionHelper } from '@features/question/services/question-helper';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
 
 /**
  * Handler to support multianswer question type.
@@ -54,7 +55,7 @@ export class AddonQtypeMultiAnswerHandlerService implements CoreQuestionHandler
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // Get all the inputs in the question to check if they've all been answered.
         const names = CoreQuestion.getBasicAnswers<boolean>(
             CoreQuestionHelper.getAllInputNamesFromHtml(question.html || ''),
@@ -62,11 +63,11 @@ export class AddonQtypeMultiAnswerHandlerService implements CoreQuestionHandler
         for (const name in names) {
             const value = answers[name];
             if (!value) {
-                return 0;
+                return QuestionCompleteGradableResponse.NO;
             }
         }
 
-        return 1;
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
@@ -82,16 +83,16 @@ export class AddonQtypeMultiAnswerHandlerService implements CoreQuestionHandler
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         // We should always get a value for each select so we can assume we receive all the possible answers.
         for (const name in answers) {
             const value = answers[name];
             if (value || value === false) {
-                return 1;
+                return QuestionCompleteGradableResponse.YES;
             }
         }
 
-        return 0;
+        return QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -109,19 +110,34 @@ export class AddonQtypeMultiAnswerHandlerService implements CoreQuestionHandler
      * @inheritdoc
      */
     validateSequenceCheck(question: CoreQuestionQuestionParsed, offlineSequenceCheck: string): boolean {
-        if (question.sequencecheck == Number(offlineSequenceCheck)) {
+        const offlineSequenceCheckNumber = Number(offlineSequenceCheck);
+        if (question.sequencecheck === offlineSequenceCheckNumber) {
             return true;
         }
 
         // For some reason, viewing a multianswer for the first time without answering it creates a new step "todo".
         // We'll treat this case as valid.
-        if (question.sequencecheck == 2 && question.state == 'todo' && offlineSequenceCheck == '1') {
+        if (question.sequencecheck === 2 && question.state === 'todo' && offlineSequenceCheckNumber === 1) {
             return true;
         }
 
         return false;
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isCompleteResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_multianswer.pleaseananswerallparts');
+    }
+
 }
 
 export const AddonQtypeMultiAnswerHandler = makeSingleton(AddonQtypeMultiAnswerHandlerService);
diff --git a/src/addons/qtype/multichoice/component/multichoice.ts b/src/addons/qtype/multichoice/component/multichoice.ts
index 3a615401de3..4059d3d7387 100644
--- a/src/addons/qtype/multichoice/component/multichoice.ts
+++ b/src/addons/qtype/multichoice/component/multichoice.ts
@@ -35,6 +35,7 @@ export class AddonQtypeMultichoiceComponent extends CoreQuestionBaseComponent<Ad
      */
     init(): void {
         this.initMultichoiceComponent();
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/multichoice/lang.json b/src/addons/qtype/multichoice/lang.json
new file mode 100644
index 00000000000..1a37dd96a7f
--- /dev/null
+++ b/src/addons/qtype/multichoice/lang.json
@@ -0,0 +1,4 @@
+{
+    "pleaseselectananswer": "Please select an answer.",
+    "pleaseselectatleastoneanswer": "Please select at least one answer."
+}
diff --git a/src/addons/qtype/multichoice/services/handlers/multichoice.ts b/src/addons/qtype/multichoice/services/handlers/multichoice.ts
index 9a02f2e2fd4..5c39ac184f4 100644
--- a/src/addons/qtype/multichoice/services/handlers/multichoice.ts
+++ b/src/addons/qtype/multichoice/services/handlers/multichoice.ts
@@ -18,7 +18,9 @@ import { AddonModQuizMultichoiceQuestion } from '@features/question/classes/base
 import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { CoreObject } from '@singletons/object';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
+import { CoreUtils } from '@singletons/utils';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support multichoice question type.
@@ -44,15 +46,15 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         let isSingle = true;
         let isMultiComplete = false;
 
         // To know if it's single or multi answer we need to search for answers with "choice" in the name.
         for (const name in answers) {
-            if (name.indexOf('choice') != -1) {
+            if (name.indexOf('choice') !== -1) {
                 isSingle = false;
-                if (answers[name]) {
+                if (CoreUtils.isTrueOrOne(answers[name])) {
                     isMultiComplete = true;
                 }
             }
@@ -63,7 +65,7 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
             return this.isCompleteResponseSingle(answers);
         } else {
             // Multi.
-            return isMultiComplete ? 1 : 0;
+            return isMultiComplete ? QuestionCompleteGradableResponse.YES : QuestionCompleteGradableResponse.NO;
         }
     }
 
@@ -73,8 +75,10 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
      * @param answers The question answers (without prefix).
      * @returns 1 if complete, 0 if not complete, -1 if cannot determine.
      */
-    isCompleteResponseSingle(answers: CoreQuestionsAnswers): number {
-        return (answers.answer && answers.answer !== '') ? 1 : 0;
+    isCompleteResponseSingle(answers: CoreQuestionsAnswers): QuestionCompleteGradableResponse {
+        return (answers.answer && answers.answer !== '')
+            ? QuestionCompleteGradableResponse.YES
+            : QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -90,7 +94,7 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         return this.isCompleteResponse(question, answers);
     }
 
@@ -101,7 +105,7 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
      * @param answers Object with the question answers (without prefix).
      * @returns 1 if gradable, 0 if not gradable, -1 if cannot determine.
      */
-    isGradableResponseSingle(answers: CoreQuestionsAnswers): number {
+    isGradableResponseSingle(answers: CoreQuestionsAnswers): QuestionCompleteGradableResponse {
         return this.isCompleteResponseSingle(answers);
     }
 
@@ -160,6 +164,22 @@ export class AddonQtypeMultichoiceHandlerService implements CoreQuestionHandler
         }
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: AddonModQuizMultichoiceQuestion,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isGradableResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return question.multi
+            ? Translate.instant('addon.qtype_multichoice.pleaseselectatleastoneanswer')
+            : Translate.instant('addon.qtype_multichoice.pleaseselectananswer');
+    }
+
 }
 
 export const AddonQtypeMultichoiceHandler = makeSingleton(AddonQtypeMultichoiceHandlerService);
diff --git a/src/addons/qtype/calculated/component/addon-qtype-calculated.html b/src/addons/qtype/numerical/component/numerical.html
similarity index 96%
rename from src/addons/qtype/calculated/component/addon-qtype-calculated.html
rename to src/addons/qtype/numerical/component/numerical.html
index e9a643c33f1..15b8fc98a21 100644
--- a/src/addons/qtype/calculated/component/addon-qtype-calculated.html
+++ b/src/addons/qtype/numerical/component/numerical.html
@@ -1,4 +1,4 @@
-<ion-list class="addon-qtype-calculated-container" *ngIf="question && (question.text || question.text === '')">
+<ion-list class="addon-qtype-numerical-container" *ngIf="question && (question.text || question.text === '')">
     <ion-item class="ion-text-wrap">
         <ion-label>
             <core-format-text [component]="component" [componentId]="componentId" [text]="question.text" [contextLevel]="contextLevel"
diff --git a/src/addons/qtype/calculated/component/calculated.scss b/src/addons/qtype/numerical/component/numerical.scss
similarity index 100%
rename from src/addons/qtype/calculated/component/calculated.scss
rename to src/addons/qtype/numerical/component/numerical.scss
diff --git a/src/addons/qtype/calculated/component/calculated.ts b/src/addons/qtype/numerical/component/numerical.ts
similarity index 63%
rename from src/addons/qtype/calculated/component/calculated.ts
rename to src/addons/qtype/numerical/component/numerical.ts
index 1b5121a6ffe..3f8aef6ccca 100644
--- a/src/addons/qtype/calculated/component/calculated.ts
+++ b/src/addons/qtype/numerical/component/numerical.ts
@@ -14,20 +14,20 @@
 
 import { Component, ElementRef } from '@angular/core';
 
-import { AddonModQuizCalculatedQuestion, CoreQuestionBaseComponent } from '@features/question/classes/base-question-component';
+import { AddonModQuizNumericalQuestion, CoreQuestionBaseComponent } from '@features/question/classes/base-question-component';
 
 /**
- * Component to render a calculated question.
+ * Component to render a numerical question.
  */
 @Component({
-    selector: 'addon-qtype-calculated',
-    templateUrl: 'addon-qtype-calculated.html',
-    styleUrl: 'calculated.scss',
+    selector: 'numerical',
+    templateUrl: 'numerical.html',
+    styleUrl: 'numerical.scss',
 })
-export class AddonQtypeCalculatedComponent extends CoreQuestionBaseComponent<AddonModQuizCalculatedQuestion> {
+export class AddonQtypeNumericalComponent extends CoreQuestionBaseComponent<AddonModQuizNumericalQuestion> {
 
     constructor(elementRef: ElementRef) {
-        super('AddonQtypeCalculatedComponent', elementRef);
+        super('AddonQtypeNumericalComponent', elementRef);
     }
 
     /**
@@ -35,6 +35,7 @@ export class AddonQtypeCalculatedComponent extends CoreQuestionBaseComponent<Add
      */
     init(): void {
         this.initCalculatedComponent();
+        this.onReadyPromise.resolve();
     }
 
 }
diff --git a/src/addons/qtype/numerical/lang.json b/src/addons/qtype/numerical/lang.json
new file mode 100644
index 00000000000..1a38aad08b4
--- /dev/null
+++ b/src/addons/qtype/numerical/lang.json
@@ -0,0 +1,6 @@
+{
+    "pleaseenterananswer": "Please enter an answer.",
+    "invalidnumber": "You must enter a valid number.",
+    "unitnotselected": "You must select a unit.",
+    "invalidnumbernounit": "You must enter a valid number. Do not include a unit in your response."
+}
diff --git a/src/addons/qtype/numerical/numerical.module.ts b/src/addons/qtype/numerical/numerical.module.ts
index f13ba4fbe71..2313768f778 100644
--- a/src/addons/qtype/numerical/numerical.module.ts
+++ b/src/addons/qtype/numerical/numerical.module.ts
@@ -16,9 +16,15 @@ import { APP_INITIALIZER, NgModule } from '@angular/core';
 
 import { CoreQuestionDelegate } from '@features/question/services/question-delegate';
 import { AddonQtypeNumericalHandler } from './services/handlers/numerical';
+import { CoreSharedModule } from '@/core/shared.module';
+import { AddonQtypeNumericalComponent } from './component/numerical';
 
 @NgModule({
     declarations: [
+        AddonQtypeNumericalComponent,
+    ],
+    imports: [
+        CoreSharedModule,
     ],
     providers: [
         {
@@ -29,5 +35,8 @@ import { AddonQtypeNumericalHandler } from './services/handlers/numerical';
             },
         },
     ],
+    exports: [
+        AddonQtypeNumericalComponent,
+    ],
 })
 export class AddonQtypeNumericalModule {}
diff --git a/src/addons/qtype/numerical/services/handlers/numerical.ts b/src/addons/qtype/numerical/services/handlers/numerical.ts
index 122d4db9d3e..496d702f9e3 100644
--- a/src/addons/qtype/numerical/services/handlers/numerical.ts
+++ b/src/addons/qtype/numerical/services/handlers/numerical.ts
@@ -12,21 +12,238 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Injectable } from '@angular/core';
-
-import { AddonQtypeCalculatedHandlerService } from '@addons/qtype/calculated/services/handlers/calculated';
-import { makeSingleton } from '@singletons';
+import { Injectable, Type } from '@angular/core';
+import { CoreQuestionHandler } from '@features/question/services/question-delegate';
+import { makeSingleton, Translate } from '@singletons';
+import { convertTextToHTMLElement } from '@/core/utils/create-html-element';
+import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
+import { CoreObject } from '@singletons/object';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support numerical question type.
- * This question type depends on calculated question type.
  */
 @Injectable({ providedIn: 'root' })
-export class AddonQtypeNumericalHandlerService extends AddonQtypeCalculatedHandlerService {
+export class AddonQtypeNumericalHandlerService implements CoreQuestionHandler {
+
+    static readonly UNITINPUT = '0';
+    static readonly UNITRADIO = '1';
+    static readonly UNITSELECT = '2';
+    static readonly UNITNONE = '3';
+
+    static readonly UNITGRADED = '1';
+    static readonly UNITOPTIONAL = '0';
 
     name = 'AddonQtypeNumerical';
     type = 'qtype_numerical';
 
+    /**
+     * @inheritdoc
+     */
+    async getComponent(): Promise<Type<unknown>> {
+        const { AddonQtypeNumericalComponent } = await import('../../component/numerical');
+
+        return AddonQtypeNumericalComponent;
+    }
+
+    /**
+     * Check if the units are in a separate field for the question.
+     *
+     * @param question Question.
+     * @returns Whether units are in a separate field.
+     */
+    protected hasSeparateUnitField(question: CoreQuestionQuestionParsed): boolean {
+        if (!question.parsedSettings) {
+            const element = convertTextToHTMLElement(question.html);
+
+            return !!(element.querySelector('select[name*=unit]') || element.querySelector('input[type="radio"]'));
+        }
+
+        return question.parsedSettings.unitdisplay === AddonQtypeNumericalHandlerService.UNITRADIO ||
+            question.parsedSettings.unitdisplay === AddonQtypeNumericalHandlerService.UNITSELECT;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    isCompleteResponse(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): QuestionCompleteGradableResponse {
+        if (!this.isGradableResponse(question, answers)) {
+            return QuestionCompleteGradableResponse.NO;
+        }
+
+        const { answer, unit } = this.parseAnswer(question, <string> answers.answer);
+        if (answer === null) {
+            return QuestionCompleteGradableResponse.NO;
+        }
+
+        if (!question.parsedSettings) {
+            if (this.hasSeparateUnitField(question)) {
+                return this.isValidValue(<string> answers.unit)
+                    ? QuestionCompleteGradableResponse.YES
+                    : QuestionCompleteGradableResponse.NO;
+            }
+
+            // We cannot know if the answer should contain units or not.
+            return QuestionCompleteGradableResponse.UNKNOWN;
+        }
+
+        if (question.parsedSettings.unitdisplay !== AddonQtypeNumericalHandlerService.UNITINPUT && unit) {
+            // There should be no units or be outside of the input, not valid.
+            return QuestionCompleteGradableResponse.NO;
+        }
+
+        if (this.hasSeparateUnitField(question) && !this.isValidValue(<string> answers.unit)) {
+            // Unit not supplied as a separate field and it's required.
+            return QuestionCompleteGradableResponse.NO;
+        }
+
+        if (question.parsedSettings.unitdisplay === AddonQtypeNumericalHandlerService.UNITINPUT &&
+                question.parsedSettings.unitgradingtype === AddonQtypeNumericalHandlerService.UNITGRADED &&
+                !this.isValidValue(unit)) {
+            // Unit not supplied inside the input and it's required.
+            return QuestionCompleteGradableResponse.NO;
+        }
+
+        return QuestionCompleteGradableResponse.YES;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async isEnabled(): Promise<boolean> {
+        return true;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    isGradableResponse(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): QuestionCompleteGradableResponse {
+        return this.isValidValue(<string> answers.answer)
+            ? QuestionCompleteGradableResponse.YES
+            : QuestionCompleteGradableResponse.NO;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    isSameResponse(
+        question: CoreQuestionQuestionParsed,
+        prevAnswers: CoreQuestionsAnswers,
+        newAnswers: CoreQuestionsAnswers,
+    ): boolean {
+        return CoreObject.sameAtKeyMissingIsBlank(prevAnswers, newAnswers, 'answer') &&
+            CoreObject.sameAtKeyMissingIsBlank(prevAnswers, newAnswers, 'unit');
+    }
+
+    /**
+     * Check if a value is valid (not empty).
+     *
+     * @param value Value to check.
+     * @returns Whether the value is valid.
+     */
+    protected isValidValue(value: string | number | null): boolean {
+        return !!value || value === '0' || value === 0;
+    }
+
+    /**
+     * Parse an answer string.
+     *
+     * @param question Question.
+     * @param answer Answer.
+     * @returns Answer and unit.
+     */
+    protected parseAnswer(question: CoreQuestionQuestionParsed, answer: string): { answer: number | null; unit: string | null } {
+        if (!answer) {
+            return { answer: null, unit: null };
+        }
+
+        let regexString = '[+-]?(?:\\d+(?:\\.\\d*)?|\\.\\d+)(?:e[-+]?\\d+)?';
+
+        // Strip spaces (which may be thousands separators) and change other forms of writing e to e.
+        answer = answer.replace(/ /g, '');
+        answer = answer.replace(/(?:e|E|(?:x|\*|×)10(?:\^|\*\*))([+-]?\d+)/, 'e$1');
+
+        // If a '.' is present or there are multiple ',' (i.e. 2,456,789) assume ',' is a thousands separator and strip it.
+        // Else assume it is a decimal separator, and change it to '.'.
+        if (answer.indexOf('.') !== -1 || answer.split(',').length - 1 > 1) {
+            answer = answer.replace(',', '');
+        } else {
+            answer = answer.replace(',', '.');
+        }
+
+        let unitsLeft = false;
+        let match: RegExpMatchArray | null = null;
+
+        if (!question.parsedSettings || question.parsedSettings.unitsleft === null) {
+            // We don't know if units should be before or after so we check both.
+            match = answer.match(new RegExp('^' + regexString));
+            if (!match) {
+                unitsLeft = true;
+                match = answer.match(new RegExp(regexString + '$'));
+            }
+        } else {
+            unitsLeft = question.parsedSettings.unitsleft === '1';
+            regexString = unitsLeft ? regexString + '$' : '^' + regexString;
+
+            match = answer.match(new RegExp(regexString));
+        }
+
+        if (!match) {
+            return { answer: null, unit: null };
+        }
+
+        const numberString = match[0];
+        const unit = unitsLeft ? answer.substring(0, answer.length - match[0].length) : answer.substring(match[0].length);
+
+        // No need to calculate the multiplier.
+        return { answer: Number(numberString), unit };
+    }
+
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isGradableResponse(question, answers) === QuestionCompleteGradableResponse.NO) {
+            return Translate.instant('addon.qtype_numerical.pleaseenterananswer');
+        }
+
+        const { answer, unit } = this.parseAnswer(question, <string> answers.answer);
+        if (answer === null) {
+            return Translate.instant('addon.qtype_numerical.invalidnumber');
+        }
+
+        if (this.hasSeparateUnitField(question) && !this.isValidValue(<string> answers.unit)) {
+            return Translate.instant('addon.qtype_numerical.unitnotselected');
+        }
+
+        if (!question.parsedSettings) {
+            // We cannot check anything else without settings.
+            return;
+        }
+
+        if (question.parsedSettings.unitdisplay !== AddonQtypeNumericalHandlerService.UNITINPUT && unit) {
+            // There should be no units or be outside of the input, not valid.
+            return Translate.instant('addon.qtype_numerical.invalidnumbernounit');
+        }
+
+        if (question.parsedSettings.unitdisplay === AddonQtypeNumericalHandlerService.UNITINPUT &&
+            question.parsedSettings.unitgradingtype === AddonQtypeNumericalHandlerService.UNITGRADED &&
+            !this.isValidValue(unit)) {
+                return Translate.instant('addon.qtype_numerical.invalidnumber');
+        }
+
+        return;
+    }
+
 }
 
 export const AddonQtypeNumericalHandler = makeSingleton(AddonQtypeNumericalHandlerService);
diff --git a/src/addons/qtype/ordering/component/ordering.ts b/src/addons/qtype/ordering/component/ordering.ts
index 41c2bdb9400..e2293b7ce37 100644
--- a/src/addons/qtype/ordering/component/ordering.ts
+++ b/src/addons/qtype/ordering/component/ordering.ts
@@ -48,11 +48,15 @@ export class AddonQtypeOrderingComponent extends CoreQuestionBaseComponent<Addon
      */
     init(): void {
         if (!this.question) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
         const questionElement = this.initComponent();
         if (!questionElement) {
+            this.onReadyPromise.resolve();
+
             return;
         }
 
@@ -63,6 +67,7 @@ export class AddonQtypeOrderingComponent extends CoreQuestionBaseComponent<Addon
         const listContainer = questionElement.querySelector('.sortablelist');
         if (!listContainer) {
             this.logger.warn('Aborting because of an error parsing question.', this.question.slot);
+            this.onReadyPromise.resolve();
 
             return CoreQuestionHelper.showComponentError(this.onAbort);
         }
@@ -99,6 +104,7 @@ export class AddonQtypeOrderingComponent extends CoreQuestionBaseComponent<Addon
         questionElement.querySelector('.ablock')?.remove();
         inputEl?.remove();
         this.question.text = CoreDomUtils.getContentsOfElement(questionElement, '.qtext');
+        this.onReadyPromise.resolve();
     }
 
     /**
diff --git a/src/addons/qtype/ordering/services/handlers/ordering.ts b/src/addons/qtype/ordering/services/handlers/ordering.ts
index 2ff30b451a5..8d344b5ee93 100644
--- a/src/addons/qtype/ordering/services/handlers/ordering.ts
+++ b/src/addons/qtype/ordering/services/handlers/ordering.ts
@@ -17,6 +17,7 @@ import { CoreQuestionHandler } from '@features/question/services/question-delega
 import { CoreQuestion, CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { makeSingleton } from '@singletons';
 import { CoreSites } from '@services/sites';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support ordering question type.
@@ -39,8 +40,8 @@ export class AddonQtypeOrderingHandlerService implements CoreQuestionHandler {
     /**
      * @inheritdoc
      */
-    isCompleteResponse(): number {
-        return 1;
+    isCompleteResponse(): QuestionCompleteGradableResponse {
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
@@ -53,8 +54,8 @@ export class AddonQtypeOrderingHandlerService implements CoreQuestionHandler {
     /**
      * @inheritdoc
      */
-    isGradableResponse(): number {
-        return 1;
+    isGradableResponse(): QuestionCompleteGradableResponse {
+        return QuestionCompleteGradableResponse.YES;
     }
 
     /**
diff --git a/src/addons/qtype/shortanswer/component/shortanswer.ts b/src/addons/qtype/shortanswer/component/shortanswer.ts
index c955c6bd365..de256d02cab 100644
--- a/src/addons/qtype/shortanswer/component/shortanswer.ts
+++ b/src/addons/qtype/shortanswer/component/shortanswer.ts
@@ -35,6 +35,7 @@ export class AddonQtypeShortAnswerComponent extends CoreQuestionBaseComponent<Ad
      */
     init(): void {
         this.initInputTextComponent();
+        this.onReadyPromise.resolve();
     }
 
 }
diff --git a/src/addons/qtype/shortanswer/lang.json b/src/addons/qtype/shortanswer/lang.json
new file mode 100644
index 00000000000..ab64b094210
--- /dev/null
+++ b/src/addons/qtype/shortanswer/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleaseenterananswer": "Please enter an answer."
+}
diff --git a/src/addons/qtype/shortanswer/services/handlers/shortanswer.ts b/src/addons/qtype/shortanswer/services/handlers/shortanswer.ts
index 1f34de4ded5..489af9a8b5a 100644
--- a/src/addons/qtype/shortanswer/services/handlers/shortanswer.ts
+++ b/src/addons/qtype/shortanswer/services/handlers/shortanswer.ts
@@ -17,7 +17,8 @@ import { Injectable, Type } from '@angular/core';
 import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreQuestionHandler } from '@features/question/services/question-delegate';
 import { CoreObject } from '@singletons/object';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support short answer question type.
@@ -43,8 +44,8 @@ export class AddonQtypeShortAnswerHandlerService implements CoreQuestionHandler
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
-        return answers.answer ? 1 : 0;
+    ): QuestionCompleteGradableResponse {
+        return answers.answer ? QuestionCompleteGradableResponse.YES : QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -60,7 +61,7 @@ export class AddonQtypeShortAnswerHandlerService implements CoreQuestionHandler
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         return this.isCompleteResponse(question, answers);
     }
 
@@ -75,6 +76,20 @@ export class AddonQtypeShortAnswerHandlerService implements CoreQuestionHandler
         return CoreObject.sameAtKeyMissingIsBlank(prevAnswers, newAnswers, 'answer');
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isGradableResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_shortanswer.pleaseenterananswer');
+    }
+
 }
 
 export const AddonQtypeShortAnswerHandler = makeSingleton(AddonQtypeShortAnswerHandlerService);
diff --git a/src/addons/qtype/truefalse/lang.json b/src/addons/qtype/truefalse/lang.json
new file mode 100644
index 00000000000..e7bd609a82f
--- /dev/null
+++ b/src/addons/qtype/truefalse/lang.json
@@ -0,0 +1,3 @@
+{
+    "pleaseselectananswer": "Please select an answer."
+}
diff --git a/src/addons/qtype/truefalse/services/handlers/truefalse.ts b/src/addons/qtype/truefalse/services/handlers/truefalse.ts
index 7e1b7bd03cd..ff686c8566d 100644
--- a/src/addons/qtype/truefalse/services/handlers/truefalse.ts
+++ b/src/addons/qtype/truefalse/services/handlers/truefalse.ts
@@ -18,7 +18,8 @@ import { CoreQuestionHandler } from '@features/question/services/question-delega
 import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '@features/question/services/question';
 import { CoreObject } from '@singletons/object';
 import { AddonModQuizMultichoiceQuestion } from '@features/question/classes/base-question-component';
-import { makeSingleton } from '@singletons';
+import { makeSingleton, Translate } from '@singletons';
+import { QuestionCompleteGradableResponse } from '@features/question/constants';
 
 /**
  * Handler to support true/false question type.
@@ -45,8 +46,8 @@ export class AddonQtypeTrueFalseHandlerService implements CoreQuestionHandler {
     isCompleteResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
-        return answers.answer ? 1 : 0;
+    ): QuestionCompleteGradableResponse {
+        return answers.answer ? QuestionCompleteGradableResponse.YES : QuestionCompleteGradableResponse.NO;
     }
 
     /**
@@ -62,7 +63,7 @@ export class AddonQtypeTrueFalseHandlerService implements CoreQuestionHandler {
     isGradableResponse(
         question: CoreQuestionQuestionParsed,
         answers: CoreQuestionsAnswers,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         return this.isCompleteResponse(question, answers);
     }
 
@@ -90,6 +91,20 @@ export class AddonQtypeTrueFalseHandlerService implements CoreQuestionHandler {
         }
     }
 
+    /**
+     * @inheritdoc
+     */
+    getValidationError(
+        question: CoreQuestionQuestionParsed,
+        answers: CoreQuestionsAnswers,
+    ): string | undefined {
+        if (this.isGradableResponse(question, answers) === QuestionCompleteGradableResponse.YES) {
+            return;
+        }
+
+        return Translate.instant('addon.qtype_truefalse.pleaseselectananswer');
+    }
+
 }
 
 export const AddonQtypeTrueFalseHandler = makeSingleton(AddonQtypeTrueFalseHandlerService);
diff --git a/src/core/classes/promised-value.ts b/src/core/classes/promised-value.ts
index d437e841b54..c2839454937 100644
--- a/src/core/classes/promised-value.ts
+++ b/src/core/classes/promised-value.ts
@@ -122,6 +122,10 @@ export class CorePromisedValue<T = unknown> extends CorePromise<T> {
      * Reset status and value.
      */
     reset(): void {
+        if (!this.isSettled()) {
+            return;
+        }
+
         delete this.resolvedValue;
         delete this.rejectedReason;
 
diff --git a/src/core/components/dynamic-component/dynamic-component.ts b/src/core/components/dynamic-component/dynamic-component.ts
index 52dbded55d1..d888aac5340 100644
--- a/src/core/components/dynamic-component/dynamic-component.ts
+++ b/src/core/components/dynamic-component/dynamic-component.ts
@@ -28,6 +28,8 @@ import {
     KeyValueDiffer,
     Type,
 } from '@angular/core';
+import { AsyncDirective } from '@classes/async-directive';
+import { CorePromisedValue } from '@classes/promised-value';
 
 import { CoreDomUtils } from '@services/utils/dom';
 import { CoreLogger } from '@singletons/logger';
@@ -63,7 +65,7 @@ import { CoreLogger } from '@singletons/logger';
     templateUrl: 'core-dynamic-component.html',
     styles: [':host { display: contents; }'],
 })
-export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck {
+export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck, AsyncDirective {
 
     @Input() component?: Type<ComponentClass>;
     @Input() data?: Record<string | number, unknown>;
@@ -77,13 +79,18 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
         setTimeout(() => this.createComponent());
     }
 
-    instance?: any; // eslint-disable-line @typescript-eslint/no-explicit-any
+    protected promisedInstance = new CorePromisedValue<any>(); // eslint-disable-line @typescript-eslint/no-explicit-any
+
     container?: ViewContainerRef;
 
     protected logger: CoreLogger;
     protected differ: KeyValueDiffer<unknown, unknown>; // To detect changes in the data input.
     protected lastComponent?: Type<unknown>;
 
+    get instance(): any { // eslint-disable-line @typescript-eslint/no-explicit-any
+        return this.promisedInstance.value;
+    }
+
     constructor(
         differs: KeyValueDiffers,
         protected cdr: ChangeDetectorRef,
@@ -101,7 +108,7 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
         if (changes.component && !this.component) {
             // Component not set, destroy the instance if any.
             this.lastComponent = undefined;
-            this.instance = undefined;
+            this.promisedInstance.reset();
             this.container?.clear();
         } else if (changes.component && (!this.instance || this.component != this.lastComponent)) {
             this.createComponent();
@@ -112,18 +119,31 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
      * @inheritdoc
      */
     ngDoCheck(): void {
-        if (this.instance) {
-            // Check if there's any change in the data object.
-            const changes = this.differ.diff(this.data || {});
-            if (changes) {
-                this.setInputData();
-                if (this.instance.ngOnChanges) {
-                    this.instance.ngOnChanges(CoreDomUtils.createChangesFromKeyValueDiff(changes));
-                }
+        if (!this.instance) {
+            return;
+        }
+
+        // Check if there's any change in the data object.
+        const changes = this.differ.diff(this.data || {});
+        if (changes) {
+            this.setInputData();
+            if (this.instance.ngOnChanges) {
+                this.instance.ngOnChanges(CoreDomUtils.createChangesFromKeyValueDiff(changes));
             }
         }
     }
 
+    /**
+     * @inheritdoc
+     */
+    async ready(): Promise<void> {
+        const instance = await this.promisedInstance;
+
+        if (instance && typeof instance['ready'] === 'function') {
+            await instance.ready();
+        }
+    }
+
     /**
      * Call a certain method on the component.
      *
@@ -135,11 +155,12 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
         method: Method,
         ...params: InstanceMethodParams<ComponentClass, Method>
     ): InstanceMethodReturn<ComponentClass, Method> | undefined {
-        if (typeof this.instance?.[method] !== 'function') {
+        const instance = this.instance;
+        if (typeof instance?.[method] !== 'function') {
             return;
         }
 
-        return this.instance[method].apply(this.instance, params);
+        return instance[method].apply(instance, params);
     }
 
     /**
@@ -155,7 +176,7 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
             return false;
         }
 
-        if (this.instance) {
+        if (this.promisedInstance.isSettled()) {
             // Component already instantiated.
             return true;
         }
@@ -163,17 +184,18 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
         if (this.component instanceof ComponentRef) {
             // A ComponentRef was supplied instead of the component class. Add it to the view.
             this.container.insert(this.component.hostView);
-            this.instance = this.component.instance;
 
             // This feature is usually meant for site plugins. Inject some properties.
-            this.instance['ChangeDetectorRef'] = this.cdr;
-            this.instance['componentContainer'] = this.element.nativeElement;
+            this.component.instance['ChangeDetectorRef'] = this.cdr;
+            this.component.instance['componentContainer'] = this.element.nativeElement;
+
+            this.promisedInstance.resolve(this.component.instance);
         } else {
             try {
                 // Create the component and add it to the container.
                 const componentRef = this.container.createComponent(this.component);
 
-                this.instance = componentRef.instance;
+                this.promisedInstance.resolve(componentRef.instance);
             } catch (ex) {
                 this.logger.error('Error creating component', ex);
 
@@ -190,6 +212,10 @@ export class CoreDynamicComponent<ComponentClass> implements OnChanges, DoCheck
      * Set the input data for the component.
      */
     protected setInputData(): void {
+        if (!this.instance) {
+            return;
+        }
+
         for (const name in this.data) {
             this.instance[name] = this.data[name];
         }
diff --git a/src/core/features/question/classes/base-question-component.ts b/src/core/features/question/classes/base-question-component.ts
index 91a55fdf144..ea4339f71ee 100644
--- a/src/core/features/question/classes/base-question-component.ts
+++ b/src/core/features/question/classes/base-question-component.ts
@@ -26,6 +26,8 @@ import { CoreQuestionBehaviourButton, CoreQuestionHelper, CoreQuestionQuestion }
 import { ContextLevel } from '@/core/constants';
 import { toBoolean } from '@/core/transforms/boolean';
 import { convertTextToHTMLElement } from '@/core/utils/create-html-element';
+import { CorePromisedValue } from '@classes/promised-value';
+import { AsyncDirective } from '@classes/async-directive';
 
 /**
  * Base class for components to render a question.
@@ -33,7 +35,7 @@ import { convertTextToHTMLElement } from '@/core/utils/create-html-element';
 @Component({
     template: '',
 })
-export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonModQuizQuestion> implements OnInit {
+export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonModQuizQuestion> implements OnInit, AsyncDirective {
 
     @Input() question?: T; // The question to render.
     @Input() component?: string; // The component the question belongs to.
@@ -54,6 +56,7 @@ export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonMod
 
     protected logger: CoreLogger;
     protected hostElement: HTMLElement;
+    protected onReadyPromise = new CorePromisedValue<void>();
 
     constructor(@Optional() @Inject('') logName: string, elementRef: ElementRef) {
         this.logger = CoreLogger.getInstance(logName);
@@ -82,6 +85,7 @@ export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonMod
      */
     init(): void {
         this.initComponent();
+        this.onReadyPromise.resolve();
     }
 
     /**
@@ -147,7 +151,7 @@ export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonMod
             return false;
         }
 
-        const question: AddonModQuizCalculatedQuestion = this.question;
+        const question: AddonModQuizNumericalQuestion = this.question;
         question.options = [];
 
         for (const i in radios) {
@@ -209,7 +213,7 @@ export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonMod
             return false;
         }
 
-        const question: AddonModQuizCalculatedQuestion = this.question;
+        const question: AddonModQuizNumericalQuestion = this.question;
         const selectModel: AddonModQuizQuestionSelect = {
             id: select.id,
             name: select.name,
@@ -726,12 +730,19 @@ export class CoreQuestionBaseComponent<T extends AddonModQuizQuestion = AddonMod
         return questionEl;
     }
 
+    /**
+     * @inheritdoc
+     */
+    async ready(): Promise<void> {
+        return this.onReadyPromise;
+    }
+
 }
 
 /**
  * Any possible types of question.
  */
-export type AddonModQuizQuestion = AddonModQuizCalculatedQuestion | AddonModQuizEssayQuestion | AddonModQuizTextQuestion |
+export type AddonModQuizQuestion = AddonModQuizNumericalQuestion | AddonModQuizEssayQuestion | AddonModQuizTextQuestion |
 AddonModQuizMatchQuestion | AddonModQuizMultichoiceQuestion;
 
 /**
@@ -744,7 +755,7 @@ export type AddonModQuizQuestionBasicData = CoreQuestionQuestion & {
 /**
  * Data for calculated question.
  */
-export type AddonModQuizCalculatedQuestion = AddonModQuizTextQuestion & {
+export type AddonModQuizNumericalQuestion = AddonModQuizTextQuestion & {
     select?: AddonModQuizQuestionSelect; // Select data if units use a select.
     selectFirst?: boolean; // Whether the select is first or after the input.
     options?: AddonModQuizQuestionRadioOption[]; // Options if units use radio buttons.
diff --git a/src/core/features/question/classes/base-question-handler.ts b/src/core/features/question/classes/base-question-handler.ts
index 3edcb57231d..9fdf587405f 100644
--- a/src/core/features/question/classes/base-question-handler.ts
+++ b/src/core/features/question/classes/base-question-handler.ts
@@ -16,6 +16,7 @@ import { Type } from '@angular/core';
 
 import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from '../services/question';
 import { CoreQuestionHandler } from '../services/question-delegate';
+import { QuestionCompleteGradableResponse } from '../constants';
 
 /**
  * Base handler for question types.
@@ -100,8 +101,8 @@ export class CoreQuestionBaseHandler implements CoreQuestionHandler {
         answers: CoreQuestionsAnswers, // eslint-disable-line @typescript-eslint/no-unused-vars
         component: string, // eslint-disable-line @typescript-eslint/no-unused-vars
         componentId: string | number, // eslint-disable-line @typescript-eslint/no-unused-vars
-    ): number {
-        return -1;
+    ): QuestionCompleteGradableResponse {
+        return QuestionCompleteGradableResponse.UNKNOWN;
     }
 
     /**
@@ -119,8 +120,8 @@ export class CoreQuestionBaseHandler implements CoreQuestionHandler {
         answers: CoreQuestionsAnswers, // eslint-disable-line @typescript-eslint/no-unused-vars
         component: string, // eslint-disable-line @typescript-eslint/no-unused-vars
         componentId: string | number, // eslint-disable-line @typescript-eslint/no-unused-vars
-    ): number {
-        return -1;
+    ): QuestionCompleteGradableResponse {
+        return QuestionCompleteGradableResponse.UNKNOWN;
     }
 
     /**
diff --git a/src/core/features/question/components/question/core-question.html b/src/core/features/question/components/question/core-question.html
index 57ece7558a8..76d1d2c72a2 100644
--- a/src/core/features/question/components/question/core-question.html
+++ b/src/core/features/question/components/question/core-question.html
@@ -1,5 +1,5 @@
 <!-- Question contents. -->
-<core-dynamic-component *ngIf="loaded" [component]="componentClass" [data]="data" class="core-question-{{question?.slot}}">
+<core-dynamic-component *ngIf="showQuestion" [component]="componentClass" [data]="data" class="core-question-{{question?.slot}}">
     <!-- This content will only be shown if there's no component to render the question. -->
     <p class="ion-padding">{{ 'core.question.errorquestionnotsupported' | translate:{$a: question?.type} }}</p>
 </core-dynamic-component>
diff --git a/src/core/features/question/components/question/question.ts b/src/core/features/question/components/question/question.ts
index e1ac05885a1..49516e39a0f 100644
--- a/src/core/features/question/components/question/question.ts
+++ b/src/core/features/question/components/question/question.ts
@@ -14,8 +14,7 @@
 
 import { ContextLevel } from '@/core/constants';
 import { toBoolean } from '@/core/transforms/boolean';
-import { Component, Input, Output, OnInit, EventEmitter, ChangeDetectorRef, Type, ElementRef } from '@angular/core';
-import { AsyncDirective } from '@classes/async-directive';
+import { Component, Input, Output, OnInit, EventEmitter, ChangeDetectorRef, Type, ElementRef, ViewChild } from '@angular/core';
 import { CorePromisedValue } from '@classes/promised-value';
 import { CoreQuestionBehaviourDelegate } from '@features/question/services/behaviour-delegate';
 import { CoreQuestionDelegate } from '@features/question/services/question-delegate';
@@ -26,6 +25,10 @@ import { CorePromiseUtils } from '@singletons/promise-utils';
 import { Translate } from '@singletons';
 import { CoreDirectivesRegistry } from '@singletons/directives-registry';
 import { CoreLogger } from '@singletons/logger';
+import { CoreObject } from '@singletons/object';
+import { CoreDynamicComponent } from '@components/dynamic-component/dynamic-component';
+import { CoreQuestionBaseComponent } from '@features/question/classes/base-question-component';
+import { AsyncDirective } from '@classes/async-directive';
 
 /**
  * Component to render a question.
@@ -51,37 +54,53 @@ export class CoreQuestionComponent implements OnInit, AsyncDirective {
     @Output() buttonClicked = new EventEmitter<CoreQuestionBehaviourButton>(); // Will emit when a behaviour button is clicked.
     @Output() onAbort= new EventEmitter<void>(); // Will emit an event if the question should be aborted.
 
+    @ViewChild(CoreDynamicComponent)
+        set dynComponent(el: CoreDynamicComponent<CoreQuestionBaseComponent>) {
+            if (!el) {
+                return;
+            }
+
+            this.promisedDynamicComponent.resolve(el);
+        }
+
     componentClass?: Type<unknown>; // The class of the component to render.
     data: Record<string, unknown> = {}; // Data to pass to the component.
     seqCheck?: { name: string; value: string }; // Sequenche check name and value (if any).
     behaviourComponents?: Type<unknown>[] = []; // Components to render the question behaviour.
-    promisedReady: CorePromisedValue<void>;
 
     validationError?: string;
 
+    protected promisedDynamicComponent = new CorePromisedValue<CoreDynamicComponent<CoreQuestionBaseComponent>>();
+    protected showQuestionPromise = new CorePromisedValue<void>();
+
     protected logger: CoreLogger;
 
-    get loaded(): boolean {
-        return this.promisedReady.isResolved();
+    get showQuestion(): boolean {
+        return this.showQuestionPromise.isResolved();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    async ready(): Promise<void> {
+        await this.showQuestionPromise;
+        const dynamicComponent = await this.promisedDynamicComponent;
+
+        return dynamicComponent.ready();
     }
 
     constructor(protected changeDetector: ChangeDetectorRef, private element: ElementRef) {
         this.logger = CoreLogger.getInstance('CoreQuestionComponent');
-        this.promisedReady = new CorePromisedValue();
         CoreDirectivesRegistry.register(this.element.nativeElement, this);
     }
 
-    async ready(): Promise<void> {
-        await this.promisedReady;
-    }
-
     /**
      * @inheritdoc
      */
     async ngOnInit(): Promise<void> {
-        if (!this.question || (this.question.type != 'random' &&
+        if (!this.question || (this.question.type !== 'random' &&
                 !CoreQuestionDelegate.isQuestionSupported(this.question.type))) {
-            this.promisedReady.resolve();
+            this.showQuestionPromise.resolve();
 
             return;
         }
@@ -92,10 +111,11 @@ export class CoreQuestionComponent implements OnInit, AsyncDirective {
         );
 
         if (!this.componentClass) {
-            this.promisedReady.resolve();
+            this.showQuestionPromise.resolve();
 
             return;
         }
+
         // Set up the data needed by the question and behaviour components.
         this.data = {
             question: this.question,
@@ -142,20 +162,9 @@ export class CoreQuestionComponent implements OnInit, AsyncDirective {
 
         CoreQuestionHelper.extractQbehaviourRedoButton(this.question);
 
-        // Extract the validation error of the question.
-        this.validationError = CoreQuestionHelper.getValidationErrorFromHtml(this.question.html);
-
         // Load local answers if offline is enabled.
         if (this.offlineEnabled && this.component && this.attemptId) {
             await CoreQuestionHelper.loadLocalAnswers(this.question, this.component, this.attemptId);
-
-            this.validationError = CoreQuestionDelegate.getValidationError(
-                this.question,
-                this.question.localAnswers || {},
-                this.validationError,
-                this.component,
-                this.attemptId,
-            );
         } else {
             this.question.localAnswers = {};
         }
@@ -175,7 +184,36 @@ export class CoreQuestionComponent implements OnInit, AsyncDirective {
             );
         } finally {
             this.question.html = CoreDomUtils.removeElementFromHtml(this.question.html, '.im-controls');
-            this.promisedReady.resolve();
+            this.showQuestionPromise.resolve();
+            await this.loadValidationError();
+        }
+    }
+
+    /**
+     * Load the validation error of the question.
+     */
+    async loadValidationError(): Promise<void> {
+        if (!this.question) {
+            return;
+        }
+
+        // Ensure question is completely initialized.
+        await this.ready();
+
+        // Extract the validation error of the question.
+        this.validationError = CoreQuestionHelper.getValidationErrorFromHtml(this.question.html);
+
+        // Load local answers if offline is enabled.
+        if (this.offlineEnabled && this.component && this.attemptId) {
+            if (this.question.localAnswers && !CoreObject.isEmpty(this.question.localAnswers)) {
+                this.validationError = CoreQuestionDelegate.getValidationError(
+                    this.question,
+                    this.question.localAnswers,
+                    this.validationError,
+                    this.component,
+                    this.attemptId,
+                );
+            }
         }
     }
 
diff --git a/src/core/features/question/constants.ts b/src/core/features/question/constants.ts
index 11743566159..ea16b58484f 100644
--- a/src/core/features/question/constants.ts
+++ b/src/core/features/question/constants.ts
@@ -37,3 +37,12 @@ export const enum QuestionDisplayOptionsValues {
     VISIBLE = 1,
     EDITABLE = 2,
 }
+
+/**
+ * Possible values for the question complete response or gradable response (compatible).
+ */
+export const enum QuestionCompleteGradableResponse {
+    UNKNOWN = -1,
+    NO = 0,
+    YES = 1,
+}
diff --git a/src/core/features/question/services/question-delegate.ts b/src/core/features/question/services/question-delegate.ts
index a1e374e5f0a..e041acc43b4 100644
--- a/src/core/features/question/services/question-delegate.ts
+++ b/src/core/features/question/services/question-delegate.ts
@@ -19,6 +19,7 @@ import { CoreWSFile } from '@services/ws';
 import { makeSingleton } from '@singletons';
 import { CoreQuestionDefaultHandler } from './handlers/default-question';
 import { CoreQuestionQuestionParsed, CoreQuestionsAnswers } from './question';
+import { QuestionCompleteGradableResponse } from '../constants';
 
 /**
  * Interface that all question type handlers must implement.
@@ -59,6 +60,8 @@ export interface CoreQuestionHandler extends CoreDelegateHandler {
 
     /**
      * Check if there's a validation error with the offline data.
+     * In situations where isGradableResponse returns false, this method
+     * should generate a description of what the problem is.
      *
      * @param question The question.
      * @param answers Object with the question offline answers (without prefix).
@@ -89,7 +92,7 @@ export interface CoreQuestionHandler extends CoreDelegateHandler {
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number;
+    ): QuestionCompleteGradableResponse;
 
     /**
      * Check if a student has provided enough of an answer for the question to be graded automatically,
@@ -106,7 +109,7 @@ export interface CoreQuestionHandler extends CoreDelegateHandler {
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number;
+    ): QuestionCompleteGradableResponse;
 
     /**
      * Check if two responses are the same.
@@ -294,7 +297,7 @@ export class CoreQuestionDelegateService extends CoreDelegate<CoreQuestionHandle
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         const type = this.getTypeName(question);
 
         const isComplete = this.executeFunctionOnEnabled<number>(
@@ -303,7 +306,7 @@ export class CoreQuestionDelegateService extends CoreDelegate<CoreQuestionHandle
             [question, answers, component, componentId],
         );
 
-        return isComplete ?? -1;
+        return isComplete ?? QuestionCompleteGradableResponse.UNKNOWN;
     }
 
     /**
@@ -321,7 +324,7 @@ export class CoreQuestionDelegateService extends CoreDelegate<CoreQuestionHandle
         answers: CoreQuestionsAnswers,
         component: string,
         componentId: string | number,
-    ): number {
+    ): QuestionCompleteGradableResponse {
         const type = this.getTypeName(question);
 
         const isGradable = this.executeFunctionOnEnabled<number>(
@@ -330,7 +333,7 @@ export class CoreQuestionDelegateService extends CoreDelegate<CoreQuestionHandle
             [question, answers, component, componentId],
         );
 
-        return isGradable ?? -1;
+        return isGradable ?? QuestionCompleteGradableResponse.UNKNOWN;
     }
 
     /**