From a tiny closet in Mountain View, Sal Khan is educating the globe for free. His 1,516 videotaped mini-lectures — on topics ranging from simple addition to vector calculus and Napoleonic campaigns — ...

All products featured here are independently selected by our editors and writers. If you buy something through links on our site, Mashable may earn an affiliate commission. Khan Academy's math lessons ...

Windows/Mac/Linux: Khan Academy is pretty useful for learning about computer science, math, and many other subjects. If you'd rather learn without being tied to an internet connection, KA Lite allows ...

Opinions expressed by Entrepreneur contributors are their own. This may surprise you, but Sal Khan used to skip classes at MIT. They were too long and boring, he often thought, particularly lectures. ...