Mathamusements

Raymond Blum Illustrated by Jeff Sinclair ORIENT PAPERBACKS A Divison of Vision Books Pvt. Ltd. New Delhi • Mumbai • Hyderabad ISBN 81-222-0254-3 1st Published in Orient Paperbacks 2000 Math amusements © 1997 Raymond Blum © 1997 Illustrations Jeff Sinclair Cover design by Vision Studio Published in arrangement with Sterling Publishing Co. Inc. USA Published by Orient Paperbacks (A division of Vision Books Pvt. Ltd.) Madarsa Road, Kashmere Gate, Delhi-110 006 Printed in India at Kay Kay Printers, Delhi-110 007 Cover Printed at Ravindra Printing Press, Delhi-110 006 DEDICATION This book is lovingly dedicated to my mother, whose example taught me the importance of working hard and always doing my best. A very special thank-you to my daughter, Kate, a talented writer and editor. A NOTE TO PARENTS AND TEACHERS This book is filled with interesting and exciting math activities that will appeal to children of all abilities, ages nine and up. There are amazing number tricks, beautiful geometric designs, challenging puzzles, marvelous memory tricks, and many other mathematical amusements that will help spark children's interest in mathematics. The book is organized so that children can open it up, pick out an activity, and get started on their own. The activities have clear, uncomplicated, step-bystep instructions, so that they are easy for children to read and understand. There is a glossary for looking up unfamiliar words. Any needed supplies can easily be found in the home or at school, or they can be purchased at minimal cost. Children will enjoy sharing these fascinating activities with their family and friends or their entire math class. All of these activities have been classroom-tested, and children love them. Math teachers can use this book to supplement their math textbook to create interest and stimulate learning. When learning is fun and exciting, children become interested and are motivated to learn more. This book helps provide that motivation. 5 CONTENTS A Note to Parents and Teachers 5 Abracadabra - mathemagic trick 8 Balancing Act - symmetrical paintblots 12 Cricket Thermometer - chirping meteorologists 14 Day You Were Born - what day of the week 16 Egyptian Pyramids - challenging puzzle 18 Finger Math - multiplying on your fingers 21 Geometric Masterpieces - compass/ruler designs 24 Happy 1,000,000th Birthday - your "seconds" age 28 Impossible Knot - amazing rope trick 30 Journey to the Moon - your moon weight 32 Knuckle Months - remembering trick 34 Lightning and Thunder - how far the storm 36 Mr. Owl Ate My Metal Worm - palindromes 38 Numerology - numbers reveal your personality 41 Origami - folding a paper cube 44 Pizza Pi - the world's largest pizza 49 Quickly, What Comes Next? - a trick question 52 A Rat in the House Might Eat the Ice Cream - memory tricks 54 Spelling Bee - card trick 58 Tangram Puzzles - seven-piece puzzle 60 Unbelievable Magic - magic trick 63 Very Fast Multiplying - multiplying shortcuts 66 Walk Through a Piece of Paper - paper-cutting trick 68 X-tra Special Designs - geometric line designs 70 Your Favorite Number - calculator tricks 76 Zooming! - enlarging a cartoon 78 Answers 81 Glossary 86 Metric Conversion Chart 93 Index 94 7 ABRACADABRA Magic tricks that use numbers are called mathemagic tricks. This number trick is easy to learn and