diff --git a/pymath/calculus/fraction.py b/pymath/calculus/fraction.py
index a40ef46..07727b9 100644
--- a/pymath/calculus/fraction.py
+++ b/pymath/calculus/fraction.py
@@ -22,13 +22,14 @@ class Fraction(Explicable):
         :param denom: the denominator
 
         """
-        super(Fraction, self).__init__()
         self._num = num
         if denom == 0:
             raise ZeroDivisionError("Can't create Fraction: division by zero")
         self._denom = denom
 
         self.isNumber = 1
+        pstf_tokens = self.compute_postfix_tokens()
+        super(Fraction, self).__init__(pstf_tokens)
 
     def simplify(self):
         """Simplify the fraction
@@ -87,8 +88,7 @@ class Fraction(Explicable):
         else:
             return copy(self)
 
-    @property
-    def postfix_tokens(self):
+    def compute_postfix_tokens(self):
         """Postfix form of the fraction
 
         >>> f = Fraction(3, 5)