How can you use math to astonish your friends and family? Try the 21-card trick. Filmed for Numberphile, UC Davis Department of Mathematics Postdoc Anastasia Chavez demonstrates step-by-step how this trick works with the help of some simple math.Watch more Numberphile and more with Matt Parker including an unexpected way to inflate a balloon, the Fold & Cut Theorem, and The Brick Double-Domino Effect Explained.
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