most recent 30 from http://mathoverflow.net 2013-05-21T21:42:30Z http://mathoverflow.net/feeds/user/3734 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/9754/magic-trick-based-on-deep-mathematics/13889#13889 unknown (google) 2010-02-02T23:25:41Z 2010-02-02T23:25:41Z

<p>You may ask the person to encode something by RSA, then you decode it (you have the private key)</p> <p>OR</p> <p>To divide two 40-digit integers and give you the decimal result to 100 digits, you then use continued fractions to find the original fraction (reduced)</p> <p>OR</p> <p>To compute pq and pr where p,q,r are prime, you then find p,q,r by the Euclidean algorithm (no very deep, but it's the best i've got)</p>