diff --git a/question/type/calculated/classes/qtype_calculated_answer.php b/question/type/calculated/classes/qtype_calculated_answer.php
new file mode 100644
index 00000000000..fc42766ab56
--- /dev/null
+++ b/question/type/calculated/classes/qtype_calculated_answer.php
@@ -0,0 +1,38 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+declare(strict_types=1);
+
+namespace qtype_calculated;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->dirroot . '/question/type/numerical/question.php');
+
+/**
+ * Class to represent a calculated question answer.
+ *
+ * @package   qtype_calculated
+ * @copyright 2023 Shamim Rezaie <shamim@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class qtype_calculated_answer extends \qtype_numerical_answer {
+    /** @var int The length of the correct answer. */
+    public $correctanswerlength;
+
+    /** @var int The format of the correct answer. */
+    public $correctanswerformat;
+}
diff --git a/question/type/calculated/questiontype.php b/question/type/calculated/questiontype.php
index 76d2fc1127b..9708f9d44dd 100644
--- a/question/type/calculated/questiontype.php
+++ b/question/type/calculated/questiontype.php
@@ -332,11 +332,27 @@ class qtype_calculated extends question_type {
         }
     }
 
+    /**
+     * Initializes calculated answers for a given question.
+     *
+     * @param question_definition $question The question definition object.
+     * @param stdClass $questiondata The question data object.
+     */
+    protected function initialise_calculated_answers(question_definition $question, stdClass $questiondata) {
+        $question->answers = array();
+        if (empty($questiondata->options->answers)) {
+            return;
+        }
+        foreach ($questiondata->options->answers as $a) {
+            $question->answers[$a->id] = new \qtype_calculated\qtype_calculated_answer($a->id, $a->answer,
+                    $a->fraction, $a->feedback, $a->feedbackformat, $a->tolerance);
+        }
+    }
+
     protected function initialise_question_instance(question_definition $question, $questiondata) {
         parent::initialise_question_instance($question, $questiondata);
+        $this->initialise_calculated_answers($question, $questiondata);
 
-        question_bank::get_qtype('numerical')->initialise_numerical_answers(
-                $question, $questiondata);
         foreach ($questiondata->options->answers as $a) {
             $question->answers[$a->id]->tolerancetype = $a->tolerancetype;
             $question->answers[$a->id]->correctanswerlength = $a->correctanswerlength;
diff --git a/question/type/calculated/tests/helper.php b/question/type/calculated/tests/helper.php
index d8dbe725690..623ed446fd0 100644
--- a/question/type/calculated/tests/helper.php
+++ b/question/type/calculated/tests/helper.php
@@ -56,12 +56,11 @@ class qtype_calculated_test_helper extends question_test_helper {
         $q->questiontext = 'What is {a} + {b}?';
         $q->generalfeedback = 'Generalfeedback: {={a} + {b}} is the right answer.';
 
-        $q->answers = array(
-            13 => new qtype_numerical_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0),
-            14 => new qtype_numerical_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.',
-                    FORMAT_HTML, 0),
-            17 => new qtype_numerical_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
-        );
+        $q->answers = [
+            13 => new \qtype_calculated\qtype_calculated_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0),
+            14 => new \qtype_calculated\qtype_calculated_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.', FORMAT_HTML, 0),
+            17 => new \qtype_calculated\qtype_calculated_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
+        ];
         foreach ($q->answers as $answer) {
             $answer->correctanswerlength = 2;
             $answer->correctanswerformat = 1;
@@ -106,12 +105,11 @@ class qtype_calculated_test_helper extends question_test_helper {
         $qdata->options->unitsleft = 0;
         $qdata->options->synchronize = 0;
 
-        $qdata->options->answers = array(
-            13 => new qtype_numerical_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0.001),
-            14 => new qtype_numerical_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.',
-                    FORMAT_HTML, 0.001),
-            17 => new qtype_numerical_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
-        );
+        $qdata->options->answers = [
+            13 => new \qtype_calculated\qtype_calculated_answer(13, '{a} + {b}', 1.0, 'Very good.', FORMAT_HTML, 0.001),
+            14 => new \qtype_calculated\qtype_calculated_answer(14, '{a} - {b}', 0.0, 'Add. not subtract!.', FORMAT_HTML, 0.001),
+            17 => new \qtype_calculated\qtype_calculated_answer(17, '*', 0.0, 'Completely wrong.', FORMAT_HTML, 0),
+        ];
         foreach ($qdata->options->answers as $answer) {
             $answer->correctanswerlength = 2;
             $answer->correctanswerformat = 1;
diff --git a/question/type/numerical/question.php b/question/type/numerical/question.php
index 3acdfe44a31..16125facca0 100644
--- a/question/type/numerical/question.php
+++ b/question/type/numerical/question.php
@@ -207,10 +207,8 @@ class qtype_numerical_question extends question_graded_automatically {
         }
         foreach ($this->answers as $answer) {
             if ($answer->within_tolerance($scaledvalue)) {
-                $answer->unitisright = !is_null($multiplier);
                 return $answer;
             } else if ($answer->within_tolerance($value)) {
-                $answer->unitisright = false;
                 return $answer;
             }
         }
@@ -218,6 +216,23 @@ class qtype_numerical_question extends question_graded_automatically {
         return null;
     }
 
+    /**
+     * Checks if the provided $multiplier is appropriate for the unit of the given $value,
+     * ensuring that multiplying $value by the $multiplier yields the expected $answer.
+     *
+     * @param qtype_numerical_answer $answer The expected result when multiplying $value by the appropriate $multiplier.
+     * @param float $value The provided value
+     * @param float|null $multiplier The multiplier value for the unit of $value.
+     * @return bool Returns true if the $multiplier is correct for the unit of $value, false otherwise.
+     */
+    public function is_unit_right(qtype_numerical_answer $answer, float $value, ?float $multiplier): bool {
+        if (is_null($multiplier)) {
+            return false;
+        }
+
+        return $answer->within_tolerance($multiplier * $value);
+    }
+
     public function get_correct_answer() {
         foreach ($this->answers as $answer) {
             $state = question_state::graded_state_for_fraction($answer->fraction);
@@ -256,12 +271,14 @@ class qtype_numerical_question extends question_graded_automatically {
         list($value, $unit, $multiplier) = $this->ap->apply_units(
                 $response['answer'], $selectedunit);
 
+        /** @var qtype_numerical_answer $answer */
         $answer = $this->get_matching_answer($value, $multiplier);
         if (!$answer) {
             return array(0, question_state::$gradedwrong);
         }
 
-        $fraction = $this->apply_unit_penalty($answer->fraction, $answer->unitisright);
+        $unitisright = $this->is_unit_right($answer, $value, $multiplier);
+        $fraction = $this->apply_unit_penalty($answer->fraction, $unitisright);
         return array($fraction, question_state::graded_state_for_fraction($fraction));
     }
 
@@ -276,6 +293,7 @@ class qtype_numerical_question extends question_graded_automatically {
             $selectedunit = null;
         }
         list($value, $unit, $multiplier) = $this->ap->apply_units($response['answer'], $selectedunit);
+        /** @var qtype_numerical_answer $ans */
         $ans = $this->get_matching_answer($value, $multiplier);
 
         $resp = $response['answer'];
@@ -291,9 +309,10 @@ class qtype_numerical_question extends question_graded_automatically {
             return array($this->id => new question_classified_response(0, $resp, 0));
         }
 
-        return array($this->id => new question_classified_response($ans->id,
-                $resp,
-                $this->apply_unit_penalty($ans->fraction, $ans->unitisright)));
+        $unitisright = $this->is_unit_right($ans, $value, $multiplier);
+        return [
+            $this->id => new question_classified_response($ans->id, $resp, $this->apply_unit_penalty($ans->fraction, $unitisright))
+        ];
     }
 
     public function check_file_access($qa, $options, $component, $filearea, $args,
diff --git a/question/type/numerical/renderer.php b/question/type/numerical/renderer.php
index 98f48921c00..cedf1bf0a69 100644
--- a/question/type/numerical/renderer.php
+++ b/question/type/numerical/renderer.php
@@ -62,7 +62,8 @@ class qtype_numerical_renderer extends qtype_renderer {
                     $currentanswer, $selectedunit);
             $answer = $question->get_matching_answer($value, $multiplier);
             if ($answer) {
-                $fraction = $question->apply_unit_penalty($answer->fraction, $answer->unitisright);
+                $unitisright = $question->is_unit_right($answer, $value, $multiplier);
+                $fraction = $question->apply_unit_penalty($answer->fraction, $unitisright);
             } else {
                 $fraction = 0;
             }