I think you're allowed a basic *scientific* calculator (powers, square root, trig functions, that sort of thing) but it will likely be scrutinized. Most of the questions that require math can also be solved by other means so check your study materials carefully.
I brought a Casio FX300 for General and Extra and they looked it over but one of the VEs said he had the same calculator and it should be OK, but I didn't need to use it anyway.