Index: Lib/decimal.py
===================================================================
--- Lib/decimal.py	(revision 59809)
+++ Lib/decimal.py	(working copy)
@@ -135,6 +135,7 @@
 ]
 
 import copy as _copy
+import numbers
 
 # Rounding
 ROUND_DOWN = 'ROUND_DOWN'
@@ -497,7 +498,7 @@
 
 ##### Decimal class #######################################################
 
-class Decimal(object):
+class Decimal(numbers.Real, numbers.Inexact):
     """Floating point class for decimal arithmetic."""
 
     __slots__ = ('_exp','_int','_sign', '_is_special')
@@ -527,7 +528,7 @@
         # and the Decimal constructor still deal with tuples of
         # digits.
 
-        self = object.__new__(cls)
+        self = super(Decimal, cls).__new__(cls)
 
         # From a string
         # REs insist on real strings, so we can too.
@@ -761,11 +762,16 @@
             return NotImplemented
         return self.__cmp__(other) == 0
 
-    def __ne__(self, other):
+    def __lt__(self, other):
         if not isinstance(other, (Decimal, int, long)):
             return NotImplemented
-        return self.__cmp__(other) != 0
+        return self.__cmp__(other) < 0
 
+    def __le__(self, other):
+        if not isinstance(other, (Decimal, int, long)):
+            return NotImplemented
+        return self.__cmp__(other) <= 0
+
     def compare(self, other, context=None):
         """Compares one to another.
 
@@ -1405,6 +1411,10 @@
 
     def __int__(self):
         """Converts self to an int, truncating if necessary."""
+        return int(self.__trunc__())
+
+    def __trunc__(self):
+        """Truncates self to an int or long."""
         if self._is_special:
             if self._isnan():
                 context = getcontext()
@@ -1420,9 +1430,9 @@
     def __long__(self):
         """Converts to a long.
 
-        Equivalent to long(int(self))
+        Equivalent to long(trunc(self))
         """
-        return long(self.__int__())
+        return long(self.__trunc__())
 
     def _fix_nan(self, context):
         """Decapitate the payload of a NaN to fit the context"""
Index: Lib/numbers.py
===================================================================
--- Lib/numbers.py	(revision 59809)
+++ Lib/numbers.py	(working copy)
@@ -45,7 +45,6 @@
 
 Inexact.register(complex)
 Inexact.register(float)
-# Inexact.register(decimal.Decimal)
 
 
 class Complex(Number):
@@ -257,7 +256,6 @@
         return +self
 
 Real.register(float)
-# Real.register(decimal.Decimal)
 
 
 class Rational(Real, Exact):
Index: Lib/test/test_decimal.py
===================================================================
--- Lib/test/test_decimal.py	(revision 59809)
+++ Lib/test/test_decimal.py	(working copy)
@@ -27,6 +27,8 @@
 
 import unittest
 import glob
+import math
+import numbers
 import os, sys
 import pickle, copy
 from decimal import *
@@ -829,7 +831,15 @@
         self.assertEqual(-Decimal(45), Decimal(-45))           #  -
         self.assertEqual(abs(Decimal(45)), abs(Decimal(-45)))  # abs
 
+    def test_trunc(self):
+        self.assertEqual(int, type(trunc(Decimal("17.5"))))
+        self.assertEqual(17, trunc(Decimal("17")))
+        self.assertEqual(17, trunc(Decimal("17.0001")))
+        self.assertEqual(17, trunc(Decimal("17.999999")))
+        self.assertEqual(-17, trunc(Decimal("-17.999999")))
+        self.assertEqual(10**30, trunc(Decimal("1e30")))
 
+
 # The following are two functions used to test threading in the next class
 
 def thfunc1(cls):
@@ -1172,7 +1182,13 @@
         d = d1.max(d2)
         self.assertTrue(type(d) is Decimal)
 
+    def test_base_classes(self):
+        self.assertTrue(issubclass(Decimal, numbers.Real))
+        self.assertTrue(issubclass(Decimal, numbers.Inexact))
+        self.assertFalse(issubclass(Decimal, numbers.Rational))
+        self.assertFalse(issubclass(Decimal, numbers.Exact))
 
+
 class DecimalPythonAPItests(unittest.TestCase):
 
     def test_pickle(self):