A global teacher of 1,516 lessons and counting
Sunday, June 27, 2010 - 13:56
in Mathematics & Economics
From a tiny closet in Mountain View, Calif., 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 -- are transforming the former hedge fund analyst into a YouTube sensation, reaping praise from even reluctant students across the world.