diff --git a/app/scodoc/sco_compute_moy.py b/app/scodoc/sco_compute_moy.py
index d9012c4bc..cb0f27384 100644
--- a/app/scodoc/sco_compute_moy.py
+++ b/app/scodoc/sco_compute_moy.py
@@ -146,7 +146,7 @@ def compute_user_formula(
         nbabs, nbabs_just = 0, 0
     try:
         moy_val = float(moy)
-    except:
+    except ValueError:
         moy_val = 0.0  # 0. when no valid value
     variables = {
         "cmask": coefs_mask,  # NoteVector(v=coefs_mask),
@@ -162,8 +162,8 @@ def compute_user_formula(
     }
     try:
         formula = formula.replace("\n", "").replace("\r", "")
-        # log('expression : %s\nvariables=%s\n' % (formula, variables)) # XXX debug
-        user_moy = sco_formulas.eval_user_expression(context, formula, variables)
+        # log('expression : %s\nvariables=%s\n' % (formula, variables)) #  debug
+        user_moy = sco_formulas.eval_user_expression(formula, variables)
         # log('user_moy=%s' % user_moy)
         if user_moy != "NA0" and user_moy != "NA":
             user_moy = float(user_moy)
diff --git a/app/scodoc/sco_formulas.py b/app/scodoc/sco_formulas.py
index f463c4dbc..2a4e49ecc 100644
--- a/app/scodoc/sco_formulas.py
+++ b/app/scodoc/sco_formulas.py
@@ -73,7 +73,7 @@ class NoteVector(object):
         """Append a value to the vector."""
         try:
             v = float(value)
-        except:
+        except ValueError:
             v = 0.0
         self.v.append(v)
         if name:
@@ -99,10 +99,20 @@ class NoteVector(object):
     __rmul__ = __mul__
 
     def __div__(self, x):
-        return binary_op(self.v, x, operator.div)
+        return binary_op(self.v, x, operator.truediv)
+
+    __truediv__ = __div__  # for py3
+
+    def __floordiv__(self, x):
+        return binary_op(self.v, x, operator.floordiv)
 
     def __rdiv__(self, x):
-        return binary_op(x, self.v, operator.div)
+        return binary_op(x, self.v, operator.truediv)
+
+    __rtruediv__ = __rdiv__  # for py3
+
+    def __rfloordiv__(self, x):
+        return binary_op(x, self.v, operator.floordiv)
 
 
 def isScalar(x):
@@ -169,7 +179,7 @@ formula_builtins = {
 # eval("max(4,5)", {'__builtins__': formula_builtins, {'x' : 1, 'v' : NoteVector(1,2) }, {})
 
 
-def eval_user_expression(context, expression, variables):
+def eval_user_expression(expression, variables):
     """Evalue l'expression (formule utilisateur) avec les variables (dict) données."""
     variables["__builtins__"] = formula_builtins
     # log('Evaluating %s with %s' % (expression, variables))