diff --git a/Lib/rational.py b/Lib/rational.py
index 2222045..bc2259b 100755
--- a/Lib/rational.py
+++ b/Lib/rational.py
@@ -43,7 +43,7 @@
 
     """
 
-    __slots__ = ('numerator', 'denominator')
+    __slots__ = ('_numerator', '_denominator')
 
     # We're immutable, so use __new__ not __init__
     def __new__(cls, numerator=0, denominator=1):
@@ -93,8 +93,8 @@
             raise ZeroDivisionError('Rational(%s, 0)' % numerator)
 
         g = gcd(numerator, denominator)
-        self.numerator = int(numerator // g)
-        self.denominator = int(denominator // g)
+        self._numerator = int(numerator // g)
+        self._denominator = int(denominator // g)
         return self
 
     @classmethod
@@ -168,6 +168,14 @@
             result = new
         return result
 
+    @property
+    def numerator(a):
+        return a._numerator
+
+    @property
+    def denominator(a):
+        return a._denominator
+
     def __repr__(self):
         """repr(self)"""
         return ('Rational(%r,%r)' % (self.numerator, self.denominator))