WHAT S T HE POI NT OF
MAT H?
Project Editor Amanda Wyat t US Editor Kayla Dugger Lead Designer Joe Lawrence Development Editor Ben Morgan Development Designer Jacqui Swan Illustrato r Clarisse Hassan Editors Edward A ves, Steven Carton, Alexandr a di F al co Designer Sammi Richiardi Writers Ben Ffranc on Davis, Junaid Mubeen Mathematical Consultant Junaid Mubeen Historical Consultant Philip Park er Managing Editor Lisa Gillespie Managing Art Editor Owen Peyton Jones Produce r, Pre-p roduction Robert Dunn Senior Produce r Meskerem Berh ane Jacket Designer Akiko Kato Jacket Editor Emma Dawson First American Edition, 2020 Published in the United States by DK Publishing 1450 Broadway , S uite 801, New Yor k, NY 10018 Copyright 2020 Dorling Kindersley Limited DK, a Division of Pe nguin Random House LLC 20 21 22 23 24 10 9 8 7 6 5 4 3 2 1 001310504Jan/2020 All rights reserved. Without limiting the rights under the copyright r eserved above, no part of this publication may be re produced , stor ed in or intr oduced i nto a retrieval sy stem, or transmitted, in any for m, or by an y means (electroni c, mechanic al, ph otocopying, recordi ng, or otherwise), without the prior written permission of the c opyright owner . Published in Great Britain by Dorling Kinder sley Limited A catalog re cord for this book is available from t he Library o f Congress. ISBN 978-1-4654-8173-3 Printed and bound in China A WORLD OF IDEAS: SEE ALL THERE IS TO KNOW www.dk .com
WHAT S T HE POI NT OF
MAT H?
CONTENTS
6 Whats the point of math? WHAT S THE POI NT OF NUMBERS AND COUN TING? 10 How to track time 14 How to count wi th your nose How to count your cows 20 H ow to make nothing a number 24 How to be negative How to tax your cit izens 32 How to use proportions 34 How to know the unknown WHA T S T HE POINT OF SHAPES AND MEASURING? 38 How to shape up 40 H ow to use symmetry How to measure a pyramid How to measure your eld 50 How to measure the Earth 54 How to ge t a piece of pi 56 How to tell the time How to use coordinates
WHAT S THE POI NT OF PAT TERNS AND SEQUENCES? 66 H ow to predict a comet How to become a trillionaire How to use prime numbers How to go on forever 78 H ow to keep secrets WHAT S THE POI NT OF DAT A AND ST ATI STICS? How to impress with a guess 90 How to catch a cheat How to estimate the population How to change the world with d ata 102 How to compute big numbers WHA T S T HE POINT OF PROBABILITY AND L OGIC? 108 How to plan your journey 112 How to win a game show How to escape prison 120 H ow to make history 126 Glossary and answers 128 Index Some dates have bce and ce after them. These are short for Before the Common Era and Common Era. The Common Era dates from when people think Jesus was born. Where the exact date of an event is not known, c. is used. This is short for the Latin word circa , meaning around, and indicates that the date is approximate.
TELLING T IME From early humans counting passing days by tracking the moon to todays super-accurate atomic clocks that keep time to tiny fractions of a second, math is wit h us every second of every hour .
WHA T S TH E
POINT OF MA TH ?
Math has an exci ting story stre tching back many thousands of years. Studying math helps us understand how ideas have evolved throughout human history . From ancient times to today , the human races incredible progress and advancement owe a lo t to our skill and expertise wi th math. CREA TI NG ART How do you create a perfectly proportioned painting or a superbly symmetrical bui lding? Math has the answerswhet her it be the ancient Greeks Golden Ra tio or the subtle calculations needed to give a picture perspective. GROWING CRO PS From early humans trying to predict when fruit would be ripe to modern mathematical analysis that makes sure farmers get the most from their land, math helps feed us all year round. NAVIGA TI NG EARTH Maths has always helped humans navigate the world, from plot ting points on maps to the high-tech triangulation techniques that modern-day GPS systems use. MAKING MUSIC Math and music may seem worlds apart, but without math, how could we count a beat or develop a rhythm? Math helps us understand what sounds good, and what doesnt, when dierent not es t toge ther to create harmony .
SAVING LIVES Math is lit erally a lifesaverwhet her its test ing a new drug, performing complex operations, or studying a dangerous disease, doctors, nurses, and scientists couldnt save peoples lives with out a huge amount of mathematical analysis. UNDERST AN DING THE UNIVERSE Math has helped humans make sense of the universe since we rst looked up at the night sky. Our early ancestors used tallies to track the phases of the moon. Re naissance scientists studied the plane ts orbi ts. Math is the key to unlocking the secret s of our universe. MAKING MONEY From counting what people owned thousands of years ago to the sophisticated mathematical models that explain, manage, and predict international business and trade, our world today could no t exist wi thout the mathematics of economics. EXPLORING SCIENCE Putting humans, robot s, and satellit es into space cant be done with gue sswork. Astrophysicists need math to precisely calculate orbit s and trajectories to safely navigate to the moon and beyond. DESIGNING AND BUILDING How do you build somet hing that wont fall down? How do you make it both practical and attractive? Math is the foundation of each decision archit ects, builders, and engineers make. COMPUTING When Ada Lovelace wro te the worlds rst computer program, she couldnt have imagined the way her math would change the world. T oday , our TV s, smartphones, and computers make millions of calculations to allow gigabytes of data to race through high-speed internet connections.
WHAT S THE POI NT OF
NUMBERS
AND COUNTING?
Wi thout numbers to count, we wouldnt ge t very far! From the earliest days of adding up and the simple tally systems our ancestors used, to the algebraic equations used today to explain how the universe works, numbers and counting are as fundamentally important today as they were back when the study of math rst began.