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Recreational mathematics is mathematics carried out for recreation (entertainment) rather than as a strictly research and applicationbased professional activity or as a part of a student's formal education. Although it is not necessarily limited to being an endeavor for amateurs, many topics in this field require no knowledge of advanced mathematics. Recreational mathematics involves mathematical puzzles and games, often appealing to children and untrained adults and inspiring their further study of the subject.^{[1]}
The Mathematical Association of America (MAA) includes recreational mathematics as one of its seventeen Special Interest Groups, commenting:
Recreational mathematics is not easily defined because it is more than mathematics done as a diversion or playing games that involve mathematics. Recreational mathematics is inspired by deep ideas that are hidden in puzzles, games, and other forms of play. The aim of the SIGMAA on Recreational Mathematics (SIGMAARec) is to bring together enthusiasts and researchers in the myriad of topics that fall under recreational math. We will share results and ideas from our work, show that real, deep mathematics is there awaiting those who look, and welcome those who wish to become involved in this branch of mathematics.^{[2]}
Mathematical competitions (such as those sponsored by mathematical associations) are also categorized under recreational mathematics.
Some of the more wellknown topics in recreational mathematics are Rubik's Cubes, magic squares, fractals, logic puzzles and mathematical chess problems, but this area of mathematics includes the aesthetics and culture of mathematics, peculiar or amusing stories and coincidences about mathematics, and the personal lives of mathematicians.
Mathematical games are multiplayer games whose rules, strategies, and outcomes can be studied and explained using mathematics. The players of the game may not need to use explicit mathematics in order to play mathematical games. For example, Mancala is studied in the mathematical field of combinatorial game theory, but no mathematics is necessary in order to play it.
Mathematical puzzles require mathematics in order to solve them. They have specific rules, as do multiplayer games, but mathematical puzzles do not usually involve competition between two or more players. Instead, in order to solve such a puzzle, the solver must find a solution that satisfies the given conditions.
Logic puzzles and classical ciphers are common examples of mathematical puzzles. Cellular automata and fractals are also considered mathematical puzzles, even though the solver only interacts with them by providing a set of initial conditions.
As they often include or require gamelike features or thinking, mathematical puzzles are sometimes also called mathematical games.
Magic tricks based on mathematical principles can produce selfworking but surprising effects. For instance, a mathemagician might use the combinatorial properties of a deck of playing cards to guess a volunteer's selected card, or Hamming codes to identify whether a volunteer is lying.^{[3]}
Other curiosities and pastimes of nontrivial mathematical interest include:
There are many blogs and audio or video series devoted to recreational mathematics. Among the notable are the following:
Prominent practitioners and advocates of recreational mathematics have included professional and amateur mathematicians:
Full name  Last name  Born  Died  Nationality  Description 

Lewis Carroll (Charles Dodgson)  Carroll  1832  1898  English  Mathematician, puzzlist and Anglican deacon best known as the author of Alice in Wonderland and Through the LookingGlass. 
Sam Loyd  Loyd  1841  1911  American  Chess problem composer and author, described as "America's greatest puzzlist" by Martin Gardner.^{[4]} 
Henry Dudeney  Dudeney  1857  1930  English  Civil servant described as England's "greatest puzzlist".^{[5]} 
Yakov Perelman  Perelman  1882  1942  Russian  Author of many popular science and mathematics books, including Mathematics Can Be Fun. 
D. R. Kaprekar  Kaprekar  1905  1986  Indian  Discovered several results in number theory, described several classes of natural numbers including the Kaprekar, harshad and self numbers, and discovered the Kaprekar's constant 
Martin Gardner  Gardner  1914  2010  American  Popular mathematics and science writer; author of Mathematical Games, a longrunning Scientific American column. 
Raymond Smullyan  Smullyan  1919  2017  American  Logician; author of many logic puzzle books including "To Mock a Mockingbird". 
Joseph Madachy  Madachy  1927  2014  American  Longtime editor of Journal of Recreational Mathematics, author of Mathematics on Vacation. 
Solomon W. Golomb  Golomb  1932  2016  American  Mathematician and engineer, best known as the inventor of polyominoes. 
John Horton Conway  Conway  1937  2020  English  Mathematician and inventor of Conway's Game of Life, coauthor of Winning Ways, an analysis of many mathematical games. 
Lee Sallows  Sallows  1944  English  Invented geomagic squares, golygons, and selfenumerating sentences. 