diff --git a/recopytex/scripts/exam.py b/recopytex/scripts/exam.py
index 93170e9..3593538 100644
--- a/recopytex/scripts/exam.py
+++ b/recopytex/scripts/exam.py
@@ -19,6 +19,11 @@ def try_parsing_date(text, formats=["%Y-%m-%d", "%Y.%m.%d", "%Y/%m/%d"]):
     raise ValueError("no valid date format found")
 
 
+def format_question(question):
+    question["score_rate"] = float(question["score_rate"])
+    return question
+
+
 class Exam:
     def __init__(self, name, tribename, date, term, **kwrds):
         self._name = name
@@ -56,7 +61,7 @@ class Exam:
         try:
             self._exercises[name]
         except KeyError:
-            self._exercises[name] = questions
+            self._exercises[name] = format_question(questions)
         else:
             raise KeyError("The exercise already exsists. Use modify_exercise")
 
@@ -72,9 +77,9 @@ class Exam:
             raise KeyError("The exercise already exsists. Use modify_exercise")
         else:
             if append:
-                self._exercises[name] += questions
+                self._exercises[name] += format_question(questions)
             else:
-                self._exercises[name] = questions
+                self._exercises[name] = format_question(questions)
 
     @property
     def exercices(self):