diff --git a/expression.py b/expression.py
index 3ab61cf..381832f 100644
--- a/expression.py
+++ b/expression.py
@@ -7,8 +7,12 @@ class Expression :
         self.droit = droit
         
     def evalue (self) :
+        """Renvoie la valeur de l’expression."""
+        if self.gauche is None and self.droit is None :
+            return self.valeur
+        
         if self.valeur == "+" :
-            pass
+            return self.
         elif self.valeur == "*":
             pass
     
@@ -17,6 +21,17 @@ class Expression :
     
     
     def __str__ (self) :
+        """Affiche l'expression"""
         pass
     
-        
\ No newline at end of file
+    
+    
+exp = Expression('*',
+                 Expression(6, None, None),
+                 Expression('+',
+                            Expression(4, None, None),
+                            Expression(3, None, None)
+                            )
+                 )
+
+exp.evalue()
\ No newline at end of file