Hi 2015mbamission,
If you're looking to get in some basic math practice before you start focusing on GMAT-specific material, then I highly recommend that you spend some time at Khan Academy (
www.khanacademy.org). The site is completely free, easy to use and game-like (so the work is a bit more 'fun' and less academic).
On most Quant questions, the math that you'll do isn't much more complicated than basic Arithmetic, Algebra and Geometry, although there are some specialty formulas you'll need to learn and a few rare math categories that you might not have seen when you were a teenager. You don't have to be a genius to score well in the Quant section, but you really do need to have proper math knowledge and "mechanics" (the ability to physically do the math).
GMAT assassins aren't born, they're made,
Rich