micropython maths lib?

[kjm]

We've run into trouble with a line-of-best-fit equation on the gpy. Regular python gives y=999.97 for x=420

>>> x=420
>>> 236123330.633392+-3683284.06273057*x+23906.7876866458*x**2+-82.646351259391*x**3+0.160502156282077*x**4+-0.000166027946373191*x**5+0.0000000714703479619462*x**6
999.9718719124794

but the gpy returns 352

>>> x=420
>>> 236123330.633392+-3683284.06273057*x+23906.7876866458*x**2+-82.646351259391*x**3+0.160502156282077*x**4+-0.000166027946373191*x**5+0.0000000714703479619462*x**6
352.0

Wondering if anybody knows a good maths package for micropython or some other workaround?