The headquarters of what has rapidly become the largest school in the world, at 10 million students strong, is stuffed into a few large communal rooms in a decaying 1960s office building hard by the ...

Since 2006 the Khan Academy, named for its founder Salman Khan, has provided free video lectures on subjects such as mathematics, biology and history. As we've reported before Khan garnered praise ...

"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: ...