In 2006, Sal Khan started making YouTube videos meant to help his nieces with their math homework. Since then, Khan’s video collection has grown into a huge repository of tutorials used in and out of ...

The College Board, which administers the Advanced Placement program, and Khan Academy, an online nonprofit offering resources and videos, are teaming up to create a supply of free test-preparation and ...

"This," says Matthew Carpenter, "is my favorite exercise." I peer over his shoulder at his laptop screen to see the math problem the fifth grader is pondering. It's an inverse trigonometric function: ...