Salman Khan, a 33-year-old math and science whiz kid -- working out of his house in California's Silicon Valley -- may be revolutionizing how people all over the world will learn math. He's become a kind of an unseen rock star in the online instruction field, posting 1200 lessons in math and science on KZfaq, none of them lasting more than about 10 minutes. He quit his job at the hedge fund to devote full time to his Khan Academy teaching efforts, which he does essentially for free.
Khan explained how the U.S. unemployment rate is calculated in a NewsHour exclusive video.