Math explained in easy language, plus puzzles, games, quizzes, worksheets and a forum. For K-12 kids, teachers and parents.

Online Math Tools - Number Empire

The Khan Academy is a not-for-profit 501(c)(3) with the mission of providing a world-class education to anyone, anywhere. Despite being the work of o...

Purplemath contains practical algebra lessons demonstrating useful techniques and pointing out common errors. Lessons are written with the struggling ...

Dictionary.com - the largest and most trusted free online dictionary. Instantly look up accurate and extensive definitions and word meanings, and hear...

Online Dictionary - Multiple dictionaries including: English dictionary, medical dictionary, legal dictionary, financial dictionary, computer dictiona...

Smart, fun, plain-spoken study guides and teacher resources. Digital textbooks by Ph.D. and Masters students from Stanford, Harvard, Berkeley

MathWorks is the world’s leading developer of technical computing software for engineers and scientists in industry, government, and education

Comprehensive encyclopedia of mathematics with 13,000 detailed entries. Continually updated, extensively illustrated, and with interactive examples.