Add note about surprising behaviour from round function.
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 8a413f4..5c21f34 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -972,6 +972,13 @@
The return value is an integer if called with one argument, otherwise of the
same type as *x*.
+ .. note::
+
+ The behavior of :func:`round` for floats can be surprising: for example,
+ ``round(2.675, 2)`` gives ``2.67`` instead of the expected ``2.68``.
+ This is not a bug: it's a result of the fact that most decimal fractions
+ can't be represented exactly as a float. See :ref:`tut-fp-issues` for
+ more information.
.. function:: set([iterable])
:noindex: