Add link to math.fsum().
diff --git a/Doc/tutorial/floatingpoint.rst b/Doc/tutorial/floatingpoint.rst
index 98e299d..a8a4202 100644
--- a/Doc/tutorial/floatingpoint.rst
+++ b/Doc/tutorial/floatingpoint.rst
@@ -189,6 +189,16 @@
across different versions of Python (platform independence) and exchanging
data with other languages that support the same format (such as Java and C99).
+Another helpful tool is the :func:`math.fsum` function which helps mitigate
+loss-of-precision during summation. It tracks "lost digits" as values are
+added onto a running total. That can make a difference in overall accuracy
+so that the errors do not accumulate to the point where they affect the
+final total:
+
+ >>> sum([0.1] * 10) == 1.0
+ False
+ >>> math.fsum([0.1] * 10) == 1.0
+ True
.. _tut-fp-error: