diff --git a/php/classes/class-qmn-quiz-manager.php b/php/classes/class-qmn-quiz-manager.php
index 0bfc86ef6..6dfecc3b4 100644
--- a/php/classes/class-qmn-quiz-manager.php
+++ b/php/classes/class-qmn-quiz-manager.php
@@ -2404,8 +2404,8 @@ public static function check_answers( $options, $quiz_data ) {
 						$results_array = apply_filters( 'qmn_results_array', $results_array, $question );
 						// If question was graded correctly.
 						if ( ! isset( $results_array['null_review'] ) ) {
-							$points_earned += (float)$results_array['points'];
-							$answer_points += (float)$results_array['points'];
+							$points_earned += isset($results_array['points']) ? (float)$results_array['points'] : 0;
+							$answer_points += isset($results_array['points']) ? (float)$results_array['points'] : 0;
 							// If the user's answer was correct.
 							if ( isset( $results_array['correct'] ) && ( 'correct' == $results_array['correct'] ) ) {
 								$total_correct += 1;