# Mathemagic

## Mathematicians Perform 'Mathemagic' Using Basic Mathematical Principles

September 1, 2010

Mathematicians share some impressive card tricks that use basic principles of math to accomplish and wow onlookers. For instance, by using a special mathematical sequence and some simple addition, you can tell what two cards a person is holding just by knowing the sum of the cards.

## Science Insider

ABOUT THE FIBONACCI SEQUENCE: The Fibonacci sequence was identified by an Italian also known as Leonardo of Pisa. His book from 1202 explained the sequence to Europeans, though it had been previously identified by Indian mathematicians. The sequence begins with 0, then 1, after which new numbers are made by adding the two previous numbers in the sequence (The sequence begins 0,1,1,2,3,5,8,13ý). It's useful in computer algorithms and financial analysis. It appears in biological structures and even in the curve of breaking waves.

ABOUT THE "ICE CREAM" TRICK: Some tricks use math and some use illusion. For the ice cream flavor trick, Mulcahy uses the techniques of a magician to shuffle the cards while keeping track of the location of the card that started on the bottom. By manipulating its position in each shuffle, it's easy enough to identify the identity of the card atop a seemingly randomly-arranged pile.

The American Mathematical Society and the Mathematical Association of America contributed to the information contained in the TV portion of this report.

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To Go Inside This Science:
Colm Mulcahy
Spelman College
colm@spelman.edu

Mike Breen and Annette Emerson
American Mathematical Society
Providence, RI 02904-2294
paoffice@ams.org
1-800-321-4267

Ivars Peterson
Mathematical Association of America
Washington, DC 20036-1358
ipeterson@maa.org
1-800-741-9415