One deck. Fifty-two cards. How many arrangements? Let's put it this way: Any time you pick up a well shuffled deck, you are almost certainly holding an arrangement of cards that has never before existed and might not exist again. Yannay Khaikin explains how factorials allow us to pinpoint the exact (very large) number of permutations in a standard deck of cards.
4m • 2014 • TED-Ed
Why are most manhole covers round? Sure it makes them easy to roll, and slide into place in any alignment. But there’s another, more compelling reason, involving a peculiar geometric property of circles and other shapes. Marc Chamberland explains curves of constant width and Barbier’s theorem.
3m • TED-Ed
Marcus du Sautoy continues his exploration of the hidden numerical code that underpins all nature. This time it's the strange world of what happens next. Professor du Sautoy's odyssey starts with the lunar eclipse - once thought supernatural, now routinely predicted through the power of the code. But more intriguing is what the code can say about our future.
58m • The Code
A sharp, witty, mind-expanding and exuberant foray into the world of logic with computer scientist Professor Dave Cliff.