[GCC 4.5.3] on cygwin
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>>> math.sqrt(9)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'math' is not defined
>>> import math
>>> math.sqrt(9)
3.0
>>> math.sqrt('x')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: a float is required
>>> math.sqrt('9')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: a float is required
>>> math.sqrt('9.0')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: a float is required
>>>