{"id":16053,"date":"2023-09-27T10:00:06","date_gmt":"2023-09-27T14:00:06","guid":{"rendered":"https:\/\/notes.math.ca\/article\/mathematical-recreations-from-the-tournament-of-the-towns\/"},"modified":"2023-10-16T11:30:23","modified_gmt":"2023-10-16T15:30:23","slug":"mathematical-recreations-from-the-tournament-of-the-towns","status":"publish","type":"article","link":"https:\/\/notes.math.ca\/fr\/article\/mathematical-recreations-from-the-tournament-of-the-towns\/","title":{"rendered":"Mathematical Recreations from the Tournament of the Towns"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" width=\"231\" height=\"300\" src=\"https:\/\/notes.math.ca\/wp-content\/uploads\/2023\/09\/Capture-decran-2023-09-27-133520-231x300.png\" alt=\"\" loading=\"lazy\" srcset=\"https:\/\/notes.math.ca\/wp-content\/uploads\/2023\/09\/Capture-decran-2023-09-27-133520-231x300.png 231w, https:\/\/notes.math.ca\/wp-content\/uploads\/2023\/09\/Capture-decran-2023-09-27-133520.png 561w\" sizes=\"auto, (max-width: 231px) 100vw, 231px\"><\/p>\n<p>The Tournament of the Towns was first held in Moscow, Leningrad, and Riga in 1980.&nbsp; Since then it has spread to other towns and other countries. Until recently, several Canadian cities participated: &nbsp;I write this review in the hope that the Russian government will soon return to sanity, and such friendly competition may again be possible. &nbsp;<\/p>\n<p>The Tournament was founded by the late Nikolay N. Konstantinov, as a less-elitist alternative to the International Math Olympiad.&nbsp; The papers are written locally, allowing as many students as wish to to participate.&nbsp; Junior and senior students write different papers.&nbsp; Within each age group,&nbsp; there are fall and spring sessions, each consisting of an easy (\u201cO-level\u201d) paper and a harder (\u201cA-level\u201d) paper two weeks later.&nbsp; There are thus eight five-question papers a year, of which one student can write up to four. While the same problem may appear as a hard question on the junior paper and a more lightly-weighted&nbsp; easy question on the senior paper,&nbsp; the contest generates about thirty problems per year.&nbsp; This book contains all the problems from the Tournament of the Towns from Fall 2007 to Spring 2021, and their solutions. &nbsp;<\/p>\n<p>As a useful bonus, as well as the complete chronological listing, the book contains a number of suggested \u00ab\u00a0highlight\u2019\u2019 sets. In Part I of the book are eighteen themed sets with a particularly recreational flavor; in part II are selections focusing on arithmetic, geometry, and combinatorics.&nbsp;<\/p>\n<p>Tournament problems can be very difficult: the Senior A-level problems are often comparable with those on the IMO.&nbsp; They tend, however, to have more of the flavor of recreational mathematics than Olympiad problems do. Problems often involve wizards, knight, and dragons; and some problems involving a particularly counterintuitive result are hinted at by the introduction of that notorious teller of tall tales, Baron M\u00fcnchausen!&nbsp; The solver may expect to make more use of parity and the Pigeonhole Principle than of Jensen\u2019s inequality or obscure triangle geometry.<\/p>\n<figure><img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/notes.math.ca\/wp-content\/uploads\/2023\/09\/Capture-decran-2023-09-27-100121.png\" alt=\"\" width=\"243\" height=\"369\"><figcaption>By Andy Liu and Peter Taylor<br \/>\nCRC Press, Boca Raton, 2023<br \/>\n978-1-032-35292-3<\/figcaption><\/figure>\n<p>There are occasional places where the wording of a problem is not entirely clear.&nbsp; For instance, in problem S.O.3 for 2010 we find:<\/p>\n<p><em>Is it possible to cover the surface of a regular octahedron with several regular hexagons, without gaps or overlaps? <\/em><\/p>\n<p>It is, but the hexagons must be interpreted as flexible, which is nowhere stated.&nbsp; (This is presumably not the fault of the editors, but how the question appeared in the English-language version of the Tournament.) Arguably it\u2019s a better problem this way, requiring a little lateral thinking!<\/p>\n<p>On the other hand, problem C3-4 on page 45 seems to have an actual error:<\/p>\n<p><em>Alice and Betty are sixteen, Carla is fifteen, Debra is fourteen, and Ellen is thirteen. They want to cross the river in a boat. No girl may be in the boat alone, and no two girls whose ages differ by more than 2 may be in the boat at the same time. Is this task possible?<\/em><\/p>\n<p>As asked, the solution\u2019s almost trivial: Alice, Betty, Carla, and Debra cross, then Carla and Debra go back for Ellen. The given answer (requiring nine crossings) suggests that the question should have read \u201cby two or more.\u201d<\/p>\n<p>This book will be of interest to any moderately advanced math puzzler, and useful to anybody training for a math contest at the high school or university level. It should definitely be in every university and high school library, and on many private bookshelves.&nbsp; The online price is under C$75, so price should not be too much of an obstacle. (I\u2019ve seen it discounted well below this price, though it doesn\u2019t seem to be so at the time of reviewing.)<\/p>\n","protected":false},"author":11,"template":"","section":[25],"keyword":[],"class_list":["post-16053","article","type-article","status-publish","hentry","section-book-reviews"],"toolset-meta":{"author-4-info":{"author-4-surname":{"type":"textfield","raw":""},"author-4-given-names":{"type":"textfield","raw":""},"author-4-honorific":{"type":"textfield","raw":""},"author-4-institution":{"type":"textfield","raw":""},"author-4-email":{"type":"email","raw":""},"author-4-cms-role":{"type":"textfield","raw":""}},"author-3-info":{"author-3-surname":{"type":"textfield","raw":""},"author-3-given-names":{"type":"textfield","raw":""},"author-3-honorific":{"type":"textfield","raw":""},"author-3-institution":{"type":"textfield","raw":""},"author-3-email":{"type":"email","raw":""},"author-3-cms-role":{"type":"textfield","raw":""}},"author-2-info":{"author-2-surname":{"type":"textfield","raw":""},"author-2-given-names":{"type":"textfield","raw":""},"author-2-honorific":{"type":"textfield","raw":""},"author-2-institution":{"type":"textfield","raw":""},"author-2-email":{"type":"email","raw":""},"author-2-cms-role":{"type":"textfield","raw":""}},"author-info":{"author-surname":{"type":"textfield","raw":"Dawson"},"author-given-names":{"type":"textfield","raw":"Robert"},"author-honorific":{"type":"textfield","raw":"Professor"},"author-email":{"type":"email","raw":"rjmdawson@gmail.com"},"author-institution":{"type":"textfield","raw":"Saint Mary's University"},"author-cms-role":{"type":"textfield","raw":"Editor-in-Chief, CMS Notes"}},"unknown":{"downloadable-pdf":{"type":"file","raw":"https:\/\/notes.math.ca\/wp-content\/uploads\/2023\/09\/5-Mathematical-Recreations-from-the-Tournament-of-the-Towns-\u2013-CMS-Notes-1.pdf","attachment_id":16206},"article-toc-weight":{"type":"numeric","raw":"5"},"author-surname":{"type":"textfield","raw":"Dawson"},"author-given-names":{"type":"textfield","raw":"Robert"}}},"_links":{"self":[{"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/article\/16053","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/article"}],"about":[{"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/types\/article"}],"author":[{"embeddable":true,"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/users\/11"}],"version-history":[{"count":6,"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/article\/16053\/revisions"}],"predecessor-version":[{"id":16085,"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/article\/16053\/revisions\/16085"}],"wp:attachment":[{"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/media?parent=16053"}],"wp:term":[{"taxonomy":"section","embeddable":true,"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/section?post=16053"},{"taxonomy":"keyword","embeddable":true,"href":"https:\/\/notes.math.ca\/fr\/wp-json\/wp\/v2\/keyword?post=16053"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}