Mentally Calculate It: Gateways To Becoming A Human Calculator

By Alabi Stephen

This book will show you how to round a few of the corners and cut through some of the traffic while dealing with arithmetic.

The aim of this book, therefore, is to lower your dependence on a calculator and enhance your self-confidence at using your God-given devices (the mind and the brain) to compute simpler problems.

It is, therefore, my deepest hope that this book will assist towards a better understanding of the basics involved and a deeper appreciation of the wonders of playing with and manipulating numbers.

• Language: English
• Publisher: Publiseer Publishing
• Release date: Nov 15, 2017

Book preview

AUTHOR

INTRODUCTION

I cannot describe in words how excited I was the day I first saw how to multiply any two-digit number by the number 11 faster than a calculator. Let me show you. Let’s take for instance I wish to multiply 53 by 11. It is as easy as adding the digits of the two-digit number together and dropping it in their middle. So 5+3=8, and the answer to 53×11 has to be 583. Impressive, isn’t it?

This little trick or call it shortcut was what turned me to a math nut and as James Randi said, ‘Immunization against such afflictions are not available. You have to recover all by yourself. Beware.’ After learning the trick, the next thing I learned was how to square any number that ends in 5 faster and some other mind blowing magical feats.

My curiosity to know more soon overcame me and it became so unbearable until I delve into the world of studying numbers and the beautiful pattern they are capable of displaying. In the middle of my ardent quest to find out better and faster way of computing and calculating numbers, I came across one of the most important person in my life. He is my distant teacher and a professor of mathematics at Harvey Mudd College, Claremont, California. He is my greatest discovery outside of my relationship with God. He is the brain behind most of the procedures and processes laid out in this book and most mathemagic tricks of today. He popularized the term mathemagician. He is a mathematics teacher and of course a mathematics entertainer better known as a mathemagician. He is Professor Arthur Benjamin.  I read two of his books – ‘secrets of mental math’ and ‘the magic of math’. I also watched a lot of his videos and from there I learnt most of the shortcuts for doing mental math as presented to you in this book. This is why I don’t see myself as a genius or a prodigy because what I can do, I learnt from someone, and if anyone also cares enough to learn the way it is done and put in a lot of effort and practice, he would do exactly what I’m doing with relatively the same speed or even faster.

This book will show you how to round a few of the corners and cut through some of the traffic while dealing with arithmetic. One of the things that dawned on me while studying most of the mental math shortcuts was as I worked through the shortcuts I could see other ways of calculating faster and easier and with just a little bit of effort I could discover or even create new methods of my own which adds more excitements to my journey through this corner of the world of numbers.

The book is titled: Mentally calculate it – gateways to