Professor Stewart’s Hoard of Mathematical Treasures
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By the Same Author Concepts of Modern Mathematics Game, Set, and Math Does God Play Dice? Another Fine Math You’ve Got Me Into Fearful Symmetry (with Martin Golubitsky) Nature’s Numbers From Here to Infinity The Magical Maze Life’s Other Secret Flatterland What Shape Is a Snowflake? The Annotated Flatland (with Edwin A. Abbott) Math Hysteria The Mayor of Uglyville’s Dilemma Letters to a Young Mathematician How to Cut a Cake Why Beauty Is Truth Taming the Infinite Professor Stewart’s Cabinet of Mathematical Curiosities with Jack Cohen The Collapse of Chaos Figments of Reality What Does a Martian Look Like? Wheelers (science fiction) Heaven (science fiction) with Terry Pratchett and Jack Cohen The Science of Discworld The Science of Discworld II: The Globe The Science of Discworld III: Darwin’s Watch
Professor Stewart’s Hoard of Mathematical Treasures
........................................... Ian Stewart
A Member of the Perseus Books Group New York
Hardcover first published in Great Britain in 2009 by PROFILE BOOKS LTD 3A Exmouth House Pine Street London WEC1R 0JH www.profilebooks.com Paperback first published in 2010 by Basic Books, A Member of the Perseus Books Group Copyright © Joat Enterprises 2009 Text design by Sue Lamble Typeset in Stone Serif by Data Standards Ltd, Frome, Somerset. Printed and bound in Britain by Clays, Bungay, Suffolk. The moral authority of the author has been asserted. All rights reserved. Printed in the United States of America. No part of this book may be reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information, address Basic Books, 387 Park Avenue South, New York, NY 10016-8810. Books published by Basic Books are available at special discounts for bulk purchases in the United States by corporations, institutions, and other organizations. For more information, please contact the Special Markets Department at the Perseus Books Group, 2300 Chestnut Street, Suite 200, Philadelphia, PA 19103, or call (800) 810-4145, ext. 5000, or e-mail
[email protected] Hardcover ISBN: 978-1-84668-292-6 Paperback ISBN: 978-0-465-01775-1 10 9 8 7 6 5 4 3 2 1
Contents
........................................... Acknowledgements // xi Second Drawer Down . . . // 1 Calculator Curiosity 1 // 7 Year Turned Upside Down // 7 Luckless Lovelorn Lilavati // 8 Sixteen Matches // 9 Swallowing Elephants // 9 Magic Circle // 10 Dodgem // 10 Press-the-Digit-ation // 11 Secrets of the Abacus // 13 Redbeard’s Treasure // 16 Hexaflexagons // 18 Who Invented the Equals Sign? // 20 St