Khan Academy offers video lectures and accompanying discussion boards for its math component. These include videos in early math, arithmetic, algebra, geometry and calculus. Users can search for the material either by subject or by grade level.
The early math section offers videos and discussion on the most fundamental math concepts, including counting, addition and subtraction, and place value. The videos in the arithmetic section build on this material to include addition and subtraction, multiplication and division, and decimals.
Following the usual high school breakdown, Khan Academy divides its algebra section into Algebra I and Algebra II course material. There is also a special section for linear algebra.