Some kids say it makes practicing math fun. Houghton-Mifflin's Education Place Mathematics Center. Includes lesson plans for grades K-7, brain teasers, textbook support, math links, projects, and a place where kids can log on and participate in interactive math projects with other students around the world. A word list of math terms for grades 1 - 8. It has lessons with multiple choice questions.
Explanations are available for all questions.
General math, algebra, graphs, plots, geometrical stuff, trigonometry and calculus. Lessons in the basic concepts of geometry, trigonometry, and physics. Created by a high school math and physics teacher for high school students.