secrets-of-mental-math-malestrom

Prologue
by Michael Shermer
My good friend Dr. Arthur Benjamin, mathematics professor at
Harvey Mudd College in Claremont, California, takes the stage
to a round of applause at the Magic Castle, a celebrated magic
club in Hollywood, where he is about to perform “mathemagics,”
or what he calls the art of rapid mental calculation. Art
appears nothing like a mathematics professor from a prestigious
college. Astonishingly quick-witted, he looks at home with the
rest of the young magicians playing at the Castle—which he is.
What makes Art so special is that he can play in front of any
group, including professional mathematicians and magicians,
because he can do something that almost no one else can. Art
Benjamin can add, subtract, multiply, and divide numbers in his
head faster than most people can with a calculator. He can
square two-digit, three-digit, and four-digit numbers, as well as
find square roots and cube roots, without writing anything
down on paper. And he can teach you how to perform your own
mathematical magic.
Traditionally, magicians refuse to disclose how they perform
their tricks. If they did, everyone would know how they are
done and the mystery and fascination of magic would be lost.
But Art wants to get people excited about math. And he knows
that one of the best ways to do so is to let you and other readers