Learn something new, daily. Web/iOS/Android: Whether you're a student in school or a lifelong learner, using flashcards can help you retain the information you're studying. StudyBlue is a crowd-sourced collection of these study aids.
Algebra can be tough to figure out, and textbook answer keys often don't display the step-by-step solutions so crucial to learning. Mathpapa is a website that walks you through each step of an algebraic solution.