<abstract xmlns="http://www.w3.org/1999/xhtml">We consider different ways to count the number of clues in American-style crossword puzzle grids. One yields a basic parity result for symmetric square grids. Another works efficiently even for non-symmetric grids that are already numbered. We further discuss the upper limit on the number of clues in a crossword puzzle with no 2-letter answers, and open questions are given. As a bonus, a mathematically-themed crossword puzzle is included!</abstract>

Counting Clues in Crosswords

Making the Unfair Fair

<abstract xmlns="http://www.w3.org/1999/xhtml">A commonly occurring task in intelligence tests or recreational riddles is to “find the odd one out”, that is, to determine a unique element of a set of objects that is somehow special. It is somewhat arbitrary what exactly the relevant feature is that makes one object different. But once that is settled, the answer becomes obvious. Not so with a puzzle popularized by Tanya Khovanova to express her dislike for this type of puzzle. Here, it is a more complicated relation between the objects and the features that determines the odd object, because there is only one object that does not have a unique feature expression. This puzzle inspired me to look for even more complicated relations between objects, features and feature expressions that appear to be even more symmetric, but actually still single out a “special object”. This paper provides useful definitions, a theoretical basis, solution algorithms, and several examples for this kind of puzzle.</abstract>

Next Level Odd-One-Out Puzzles

Stay in Command: Optimal Play for Two Person Generala

<abstract xmlns="http://www.w3.org/1999/xhtml">A magic SET square is a 3 by 3 table of SET cards such that each row, column, diagonal, and anti-diagonal is a set. We allow the following transformations of the square: shuffling features, shuffling values within the features, rotations and reflections of the square. Under these transformations, there are 21 types of magic SET squares. We calculate the number of squares of each type. In addition, we discuss a game of SET tic-tac-toe.</abstract>

The Classification of Magic SET Squares

AHEAD OF PRINT

Volume 11 (2024): Issue 18 (March 2024)

Volume 10 (2023): Issue 17 (January 2023)

Volume 9 (2022): Issue 16 (June 2022)

Volume 8 (2021): Issue 15 (November 2021)

Volume 8 (2021): Issue 14 (October 2021)

Volume 7 (2020): Issue 13 (November 2020)

Volume 6 (2019): Issue 12 (December 2019)

Volume 6 (2019): Issue 11 (September 2019)

Volume 5 (2018): Issue 10 (December 2018)

Volume 5 (2018): Issue 9 (September 2018)

Volume 4 (2017): Issue 8 (December 2017)

Volume 4 (2017): Issue 7 (May 2017)

Volume 3 (2016): Issue 6 (December 2016)

Volume 3 (2016): Issue 5 (March 2016)

Recreational Mathematics Magazine

The Recreational Mathematics Magazine is published by the Ludus Association with the support of the　Interuniversity Centre for the History of Science and Technology. The journal is electronic and semiannual, and focuses on results that provide amusing, witty but nonetheless original and scientifically profound mathematical nuggets. The issues are published in the exact moments of the equinox. It's a magazine for mathematicians, and other mathematics lovers, who enjoy imaginative ideas, non-standard approaches, and surprising procedures. Occasionally, some papers that do not require any mathematical background will be published.  Examples of topics to be adressed include: games and puzzles, problems, mathmagic, mathematics and arts, math and fun with algorithms, reviews and news.  Recreational mathematics focuses on insight, imagination and beauty. Historically, we know that some areas of mathematics are strongly linked to recreational mathematics - probability, graph theory, number theory, etc. Thus, recreational mathematics can also be very serious. Many professional mathematicians confessed that their love for math was gained when reading the articles by Martin Gardner in Scientific American.  While there are conferences related to the subject as the amazing Gathering for Gardner, and high-quality magazines that accept recreational papers as the American Mathematical Monthly, the number of initiatives related to this important subject is not large.  This context led us to launch this magazine. We will seek to provide a quality publication. We shall endeavor to be read with pleasure. In mathematics, the most important are the underlying ideas and nothing is as exciting as an amazing idea. So, we seek sophistication, imagination and awe.  Rejection Rate   50%   Recreational Mathematics Magazine is a journal for mathematicians who enjoy imaginative ideas, non-standard approaches, and surprising procedures. The journal addresses such topics as: games and puzzles, problems, mathmagic, mathematics and arts, math and fun with algorithms.  Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process.  Target group:   researchers in the fields of games and puzzles, problems, mathmagic, mathematics and arts, math and fun with algorithms  Financed by Fundação para a Ciência e a Tecnologia, I.P./MCTES through national funds (PIDDAC) – PTDC/HAR-HIS/28627/2017, UIDB/00286/2020 and UIDB/00678/2020. 