diff --git a/question/type/calculated/edit_calculated_form.php b/question/type/calculated/edit_calculated_form.php
index cec65e8d17c..1044f432f74 100644
--- a/question/type/calculated/edit_calculated_form.php
+++ b/question/type/calculated/edit_calculated_form.php
@@ -276,7 +276,7 @@ class qtype_calculated_edit_form extends qtype_numerical_edit_form {
 
     protected function valid_answer_message($answer) {
         if (!$answer) {
-            return get_string('mustenteraformulaorstar', 'qtype_numerical');
+            return get_string('mustenteraformulaorstar', 'qtype_calculated');
         } else {
             return qtype_calculated_find_formula_errors($answer);
         }