Maths on the Back of an Envelope: Clever ways to (roughly) calculate anything

Maths on the Back of an Envelope: Clever ways to (roughly) calculate anything
Rob Eastaway

‘Another terrific book by Rob Eastaway’ SIMON SINGH ‘A delightfully accessible guide to how to play with numbers’ HANNAH FRY How many cats are there in the world? What's the chance of winning the lottery twice? And just how long does it take to count to a million? Learn how to tackle tricky maths problems with nothing but the back of an envelope, a pencil and some good old-fashioned brain power. Join Rob Eastaway as he takes an entertaining look at how to figure without a calculator. Packed with amusing anecdotes, quizzes, and handy calculation tips for every situation, Maths on the Back of an Envelope is an invaluable introduction to the art of estimation, and a welcome reminder that sometimes our own brain is the best tool we have to deal with numbers.

Copyright

HarperCollinsPublishers 1 London Bridge Street London SE1 9GF

www.harpercollins.co.uk (http://www.harpercollins.co.uk)

First published by HarperCollinsPublishers 2019

FIRST EDITION

© Rob Eastaway 2019

Cover design by Andrew Davis © HarperCollinsPublishers Ltd 2019 Cover photograph © Shutterstock.com (http://Shutterstock.com)

A catalogue record of this book is available from the British Library

Rob Eastaway asserts the moral right to be identified as the author of this work

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Source ISBN: 9780008324582

Ebook Edition © September 2019 ISBN: 9780008324599

Version 2019-08-30

CONTENTS

1  Cover (#ube9b5bb8-b01d-57f4-8048-036dba1a0d71)

2  Title Page (#u893be14e-95f5-5740-afd9-b8d58d8996fc)

3  Copyright (#u576a6c51-6ba3-5f83-b15b-ad9155b62a18)

4  Prologue: How Many Cats? (#udba157d3-b9d4-53df-a26f-8169e146f6c4)

5  THE PERILS OF PRECISION (#ue3c4e76b-a510-5b47-8813-fd8411bc5b08)

6  TOOLS OF THE TRADE (#u3cfd0fa3-b485-5582-8ac7-19d2231b1390)

7  EVERYDAY ESTIMATION (#litres_trial_promo)

8  FIGURING WITH FERMI (#litres_trial_promo)

9  LAST WORD: WHEN THE ROBOTS TAKE OVER (#litres_trial_promo)

10  Appendix (#litres_trial_promo)

11  Answers and Tips (#litres_trial_promo)

12  Endnotes (#litres_trial_promo)

13  Acknowledgements (#litres_trial_promo)

14  About the Author (#litres_trial_promo)

15  About the Publisher (#litres_trial_promo)

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