Numero is played with 64 tiles depicting the digits 0-9, the standard arithmetical operations, and the root symbol. On each turn one player plays two numbers and an operation to use on them, and their opponent can then add to it in an effort to reduce its value. The reduced value is scored. Subsequent plays are made crossing earlier ones, using some of their tiles. The rules were published in Games & Puzzles #2 (June 1972). Sets of tiles could be purchased from the magazine.