Mathway's apps for Android and iOS allow users to access math problems and solutions for a variety of problems, from basic math to statistics.
MathRef Plus and MathRef Free provide calculations, tips and examples for math formulas and problems.
Florida Virtual School's app (on Android and iOS) provides a useful study tool for high school Algebra.
ConvertPad is a unit converter for Android that works with currency, mathematics, and scientific units from all over the world.
Wolfram Alpha's applications (available on Android, Kindle, Apple and Nook) provide robust search and data computation right on your device.
Graphing Calculator is an app that allows users to turn their iOS device into a functioning graphing and scientific calculator.
Math Workout lets you practice your math skills on Android and iOS devices with short games.
MyScript Calculator lets users write out their formulas, instead of typing in numbers. The app is available for Android, iOS, and the Amazon App store.