Figuring the Joy of Numbers

164 Pages·4.012 MB·English

by  Devi Shakuntala

Shakuntala Devi
Figuring

Figuring: The Joy of Numbers
“There is a range and richness to numbers —they can
come alive, cease to be symbols written on a black
board, and lead the reader into a world of intellectual
adventure where calculations are thrilling.”
In Figuring, Shakuntala Devi dramatizes the endless
fascination of numbers and their ability to amaze and
entertain. She offers easy-to-learn short cuts —how to
add long columns in your head, multiply, divide, and
find square roots quickly, almost magically. Fractions,
decimals, and compound interest become clear and easy
to deal with.
The author takes delight in working out huge
problems mentally—sometimes even faster than
electronic computers. In Figuring she shares her secrets
with you.
Shakuntala Devi shows you a foolproof method to
guess your friends’ birthdays and how to determine the
day of the week for any date since 1582, and, sublimely
ridiculous, she “proves” that 1=2. Puzzle-lovers will
enjoy the stories of the wise temple priest who divided
17 elephants in half without bloodshed; the man who
will be 3 years older next year than he was the day
before yesterday; and the feat of describing each
number from 1 through 18 with exactly 4 fours in each
equation.
Shakuntala Devi has delighted world audiences with
her lightning-fast computations and her infectious
enthusiasm and love for numbers. No one can read this
book without falling under the spell of Figuring and of
Ms. Shakuntala Devi.
By the same author
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FIGURING
Tl?e Joyof Nurpber?
Sljakuptala Devi
Orient®
Paperbacks
OflHI I MUMBAI I HYOtRABAO
ISBN: 978-81-222-0038-6
Figuring: The Jog of Numbers
Subject: Mathematics I Recreations & Games
© Shakuntala Devi
1st Published 1986
51st Printing 2014
Published by
Orient Paperback*
(A division of Vision Books Pvt. Ltd.)
5A/8 Ansari Road, New Delhi-110 002
www orientpaperbacks.com
Cover design by Vision Studio
Printed at
Printed in India at Artxel, Noida
CONTENTS
Introduction 9
1 Some Terms Defined 11
2 The Digits 15
3 Multiplication 31
4 Addition 48
5 Division 52
6 Subtraction 60
7 GCMandLCM 62
8 Squares and Square Roots 68
9 Cubes and Cube Roots 77
10 Percentages, Discounts and Interest 87
11 Decimals 94
12 Fractions 99
13 The Calendar 104
14 Some Special Numbers 112
15 Tricks and Puzzles 131
Conclusion 157

Whatever there is in all the three worlds, which are
possessed of moving and non-moving beings, can­
not exist as apart from the ‘Ganita’ (calculation)
Mahavira (ad 850)