The Secrets of Mental Math: The mathemagician's guide to lightening calculation and amazing math tricks

Benjamin, A & Shermer, M. (2006) Secrets of Mental Math: The mathemagician’s guide to lightening calculation and amazing math tricks. Three Rivers Press, New York.

As the title states, this book explores how to amaze your friends, family, and students with rapid mental calculations. It gives tricks on how to add, subtract, multiply, and divide with ease. It also goes further and explains how one can find square roots, calculate days of the week for obscure for any date, and also gives brief historical antidotes. These tricks should be taught to everyone from an early age. Benjamin stresses the importance of breaking problems up into easier and thus more doable problems. We are taught from an early age to add, subtract and multiply from right to left, which is contrary to the way we read everything else. When we read a number it read from left to right. So, this right to left business can be confusing, Benjamin states that in order to do mental math it is of utmost importance to start the process from left to right, breaking the problem into pieces. I would highly recommend this book to improve your own calculations as well as to share these tricks with students.

“Too often, math is taught as a set of rigid rules, leaving little room for creative thinking. But as you will learn there are often several ways to solve the same problem”

The book is little talk and largely methods of calculations with several examples and ample problems to being your own practice.
To see the master do it himself check out this TED talk by the mathemagician himself Arthur Benjamin. http://www.youtube.com/watch?v=M4vqr3_ROIk