Looking for a thorough guide on how to convert between Fahrenheit and Celsius temperature scales? It's easy! And this clip will teach you everything you'll need to know. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to express a Fahrenheit temperature as degrees Celsius.