**Secrets of Mental Math - The Mathemagicians' Guide to Lightning Calculation and Amazing Math Tricks**

Author – Arthur Benjamin and Michael Shermer

**Book Review**

If you need to find a math refresher, prepare for math competitions, find another way to teach basic arithmetic that clicks for at-risk students, or find ways to show off your mental math skills, take time to read a few chapters of

*Secret of Mental Math*. If you do, you may find yourself saying, "Why didn't they teach me that in school?"

The authors share that "The fundamental principle of mental math arithmetic – namely, to simplify your problem by breaking it into smaller, more manageable parts. This is key to virtually every method you will learn in this book." As I read through some ideas I recognized that some tricks may not be new or secret to "math" people, but they are probably not common knowledge. Here's a quick one shared in chapter one, squaring a number ending in 5 requires two rules.

1) Multiply the first digit by the next higher digit

2) Append "25" to the answer

For example, 65 x 65 => the first digit is 6; so multiply 6 by the next higher number (7) to get "42" and attach "25" on the end. Thus, 65 x 65 = 4225.

Although some of the content towards the end of the book may take a few minutes to grasp, I like this book because as a teacher of Developmental Mathematics for adults and Tutor of other struggling math students, I believe my students could pick this book up on their own and be enlightened by the way

*Secrets of Mental Math*proposes another way to approach arithmetic rather than the traditional methods that alluded them in school.

Also, I believe teachers and instructors should share some of these mental tips in their classrooms as alternative ways to work a problem. I call my math tips and alternative methods "Mrs. Mackie’s Math Commercials." And yes, I saw some of my commercials in this book. For instance, recently after giving a quiz, I notice some students were multiplying 2 digit by 2 digit numbers incorrectly. Now, that particular skill isn't part of the curriculum, but I addressed it in a

*math commercial*showing the traditional algorithm and the method used in chapter 3 of

*Secrets of Mental Math*. In fact, below is the full Table of Contents:

Chapter 0 Quick Tricks: Easy (and Impressive) Calculations

Chapter 1 A Little Give and Take: Mental Addition and Subtraction

Chapter 2 Products of a Mispent Youth: Basic Multiplication

Chapter 3 New and Improved Products: Intermediate Multiplication

Chapter 4 Divide and Conquer: Mental Division

Chapter 5 Good Enough: The Art of "Guesstimation"

Chapter 6 Math for the Board: Pencil-and-Paper Math

Chapter 7 A Memorable Chapter: Memorizing Numbers

Chapter 8 The Tough Stuff Made Easy: Advanced Multiplication

Chapter 9 Presto-digit-ation: The Art of Mathematical Magic

Chapter 10 Epilogue by Michael Shermer: How Math Helps Us Think About Weird

Things

Answers

Bibliography

Index

Take a look inside the book or buy it by clicking the link below.