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Number scrabble (aka Fifteen)

See also: representations, implementing-number-scrabble, number-scrabble-web

Number Scrabble (aka Pick 15, 3 to 15, 15) is a mathematical game used by Herb Simon to demonstrate the importance of representation to design.

Two players take turns to pick a number from 1 to 9. The first player to pick three numbers that add up to 15 wins.

With the numbers represented as a sequence of scrabble tiles players must exert some effort to win. If the numbers are organised into a magic square the game is isomorphic to tic-tac-toe.

Magicsquareexample.svg Example magic square (Public Domain, Wikimedia Commons)

Use in teaching mathematics#

The game is mentioned often in the context of teaching/learning of mathematics (Mason et al, 2010; Yeo & Ban Har, 2009)

Reference#

Mason, J., Burton, L., & Stacey, K. (2010). Thinking mathematically (2nd ed). Pearson.

Michon, J. A. (1967). The Game of JAM: An Isomorph of Tic-Tac-Toe. The American Journal of Psychology, 80(1), 137. https://doi.org/10.2307/1420555

Moeler, C. (2011). TicTacToe Magic. In Experiments with MATLAB (pp. 141--150). MathWorks, Inc. https://www.mathworks.com/content/dam/mathworks/mathworks-dot-com/moler/exm/chapters/tictactoe.pdf

Yeo, J. B. W., & Ban Har, Y. (2009). Investigating the processes of mathematical investigation. 3rd Redesigning Pedagogy International Conference, Singapore. https://repository.nie.edu.sg/entities/publication/f542585b-0b92-4a70-a005-0c6dfb9303c7/details