Mathematics on Vacation By J. S. Madachy * Publisher: Scribner * Number Of Pages: 252 * Publication Date: 1975-05 (pbk of 1966 edition) * ISBN-10 / ASIN: 0684139642 * ISBN-13 / EAN: 9780684139647 preface If you have ever solved a mathematical puzzle, played any game in which numbers were used, learned a number trick, or played ticktacktoe, you have indulged in a type of mathematical recreation. In general, these recreations share three characteristics: first, they are mathematical or logical; second, they are fun; third, they all appear to be quite useless. The first two characteristics require no support, but some might ask why anyone should indulge in anything that is of no practical value. An indirect defense may be built up from the fact that the most staid mathematics and engineering journals publish some material that is strictly recreational in nature, giving the amusements a kind of endorsement. Moreover, a very cursory examination will disclose a few interesting facts about the utility of recreational mathematics. Prime numbers, for example, have no practical value. It may be decades, if ever, before such a use for them will be found. However, the study of prime numbers and their properties has filled many a gap in the field of number theory, that mathematical discipline which studies the basic properties of all numbers. Magic squares have been involved with superstitious beliefs and proven an interesting source of amusement for centuries. They, too, offer practical rewards for the agricultural and nuclear scientist. The study of the patterns of certain types of magic square has shown how to reduce the number of experiments required to obtained growth and radiation data. The classic Moebius strip has been used for conveyor belts that last twice as long as conventional belts. Indeed, the B. F. Goodrich Co. has obtained a patent for this particular use. Many areas of recreational mathematics still seem to be useless, but who can say what next year or the next decade will bring? This book attempts to give a sampling of both types of material. Much of its material is taken from the pages of Recreational Mathematics Magazine, which I founded, edited, and published from 1960 until its discontinuation in 1964. Moreover, many notes and comments from the periodical's readers as well as a number of original ideas have been incorporated here. Thanks and direct acknowledgement to the many who contributed or helped will be found in the Acknowledgements and throughout the book. Thanks must also go to]. A. H. Hunter, Howard C. Saar, and Dmitri E. Thoro who, as co-editors of Recreational Mathematics Magazine, worked far beyond the call of duty. The author wishes to express his gratitude as well to the nearly ten thousand former subscribers whose enthusiasm and support helped make this book possible. Kettering, Ohio J.S.M. 1 • GEOMETRIC DISSECTIONS 2 • CHESSBOARD PLACEMENT PROBLEMS 3 • FUN WITH PAPER geometric constructions with paper only flexagons other flexagon diversions solid flexagons 4 • MAGIC AND ANTIMAGIC SQUARES magIc squares miscellaneous magic configurations antimagic squares talisman squares contents 5 • PUZZLES AND PROBLEMS problems answers 6 • NUMBER RECREATIONS numbers and their divisors perfect and multiperfect numbers prime numbers amicable numbers 0123456789, or digital diversions narcissistic numbers factorial products printer's "errors" automorphic numbers two rather large numbers 7 • ALPHAMETICS alphametic puzzles answers 8 • CONGLOMERATE the problem of the mice deployment domino recreations lost chords bouncing billiard balls • GLOSSARY • BIBLIOGRAPHY • INDEX
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