Index: Doc/library/collections.rst
===================================================================
--- Doc/library/collections.rst	(revision 68803)
+++ Doc/library/collections.rst	(working copy)
@@ -300,6 +300,7 @@
 
 * `Bag class <http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html>`_
   in Smalltalk
+
 * `C++ multisets <http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm>`_
   tutorial with standalone examples
 
Index: Lib/numbers.py
===================================================================
--- Lib/numbers.py	(revision 68802)
+++ Lib/numbers.py	(working copy)
@@ -17,6 +17,7 @@
     caring what kind, use isinstance(x, Number).
     """
     __metaclass__ = ABCMeta
+    __slots__ = ()
 
     # Concrete numeric types must provide their own hash implementation
     __hash__ = None
@@ -41,6 +42,8 @@
     type as described below.
     """
 
+    __slots__ = ()
+
     @abstractmethod
     def __complex__(self):
         """Return a builtin complex instance. Called for complex(self)."""
@@ -172,6 +175,8 @@
     Real also provides defaults for the derived operations.
     """
 
+    __slots__ = ()
+
     @abstractmethod
     def __float__(self):
         """Any Real can be converted to a native float object.
@@ -265,6 +270,8 @@
 class Rational(Real):
     """.numerator and .denominator should be in lowest terms."""
 
+    __slots__ = ()
+
     @abstractproperty
     def numerator(self):
         raise NotImplementedError
@@ -288,6 +295,8 @@
 class Integral(Rational):
     """Integral adds a conversion to long and the bit-string operations."""
 
+    __slots__ = ()
+
     @abstractmethod
     def __long__(self):
         """long(self)"""
Index: Lib/test/test_fractions.py
===================================================================
--- Lib/test/test_fractions.py	(revision 68802)
+++ Lib/test/test_fractions.py	(working copy)
@@ -394,6 +394,11 @@
         self.assertEqual(id(r), id(copy(r)))
         self.assertEqual(id(r), id(deepcopy(r)))
 
+    def test_slots(self):
+        # Issue 4998
+        r = F(13, 7)
+        self.assertRaises(AttributeError, setattr, r, 'a', 10)
+
 def test_main():
     run_unittest(FractionTest, GcdTest)