Missing 'math' module in manim_tutorial_1.py

[quark67]

When I try to render the scene ExampleApproximation of manim_tutorial_1.py, I obtain in Terminal this error:

NameError: global name 'math' is not defined

for line 234.
Actually, big_ol_pile_of_manim_imports.py has not an import math line in the May 9, 2018 commit of manim, the manim version you suggest to use in your talkingphysics.wordpress.com tutorials.
(recent versions of manim have the line import math in big_ol_pile_of_manim_imports.py)