Calc Chat – Offers free student solutions manuals for many math textbooks by Ron Larson.
Math | Khan Academy – Free videos and practice problems for countless topics.
MIT Open Courseware – Full, recorded lectures for learning at your own pace.
PatrickJMT – Free videos for topics such as Algebra, Precalculus, Calculus, Differential Equations, and Discrete Mathematics.
Paul’s Online Math Notes – Free math notes from a Professor. Includes Algebra, Calculus I, II, III, Linear Algebra, and Differential Equations.
WolframAlpha – Solves many numerical problems for Math (including integrals, limits, and infinite series), Physics, Chemistry, Engineering, etc.
Desmos.com (Includes graphing mode)
Tydlig calculator – App for iPhone and iPad