In this entertaining TED video the mathemagician Arthur Benjamin races a team of calculators to figure out 3-digit squares. He also solves another massive mental equation and guesses a few birthdays of random people from the audience. Wondering how  that is even possible? Better watch the video to see!

Using daring displays of algorithmic trickery, lightning calculation and number wizardry, Arthur Benjamin mesmerises audiences with mathematical mystery and beauty. He is a professor of maths at Harvey Mudd College, but after work he becomes a “mathemagician” who takes the stage to perform high-speed mental calculations, memorisations and other astounding maths stunts.

Benjamin is also the co-author, with Michael Shermer, of Secrets of Mental Math (in which he shares his secrets for rapid mental calculation), as well as the co-author of the MAAaward-winning Proofs That Really Count: The Art of Combinatorial Proof.