S.O.S. MATHematics offers free resources for math reviews of algebra, pre-calculus, trigonometry, calculus, and differential equations. The emphasis is on review and reference.
Use the site to refresh your memory, or prepare for a test. There are practice tests for intermediate algebra, pre-calculus I, pre-calculus II, calculus, and differential equations. There are also practice tests for “mathematics for social sciences” which encompass matrices, annuities, and exponential and logarithmic functions,
Also on the site are reviews for the Fourier Series and several mathematical tables. The Cyberboard offers a help forum for students.