diff --git a/pylib/mathematics.py b/pylib/mathematics.py
index b8ff0c7..a2298d3 100644
--- a/pylib/mathematics.py
+++ b/pylib/mathematics.py
@@ -10,6 +10,7 @@
 
 .. moduleauthor:: Daniel Weschke <daniel.weschke@directbox.de>
 """
+import math
 from math import gcd
 
 def lcm(a, b):