Book excerpt: Mathematical Games and Pastimes focuses on numerical solutions to mathematical games and pastimes. The book first discusses the binary system of notation and the system of notation with the base three. Congruences, Pythagorean and Heronic triples, and arithmetical pastimes are explained. The text takes a look at the nature of numerical tricks. Guessing the results of operations with unknown numbers; determination of numbers thought of using three tables; and extraction of roots of multidigit numbers are explained. The selection also touches on rapid calculations, games with piles of objects, M.