Salman Khan teaches math and science via YouTube video lessons.  It’s called Khan Academy.  He teaches a wide variety of subjects including algebra, calculus, biology, physics, chemistry and statistics.  He thinks everyone should be able to get an education for free and he does not think universities are doing it properly.  The education model needs to be rethought and rebuilt.  Many people think so and that’s why Kahn Academy has so many students and is attracting venture capital money.  He’s getting more viewers than most university web sites.  Here’s a PBS NewsHour piece about him:

Here’s a lesson on adding and subtracting fractions: