Mathematics permeates the most insignificant of our actions. With the aid of mathematics we calculate percentages, fill out our tax forms, synchronize traffic lights, create the workings of the electoral system, even set up the game of lotto. The games that Elisabeth Busser and Gilles Cohen propose here are fun to play and accessible to all. While illustrating several key notions of mathematics, they humorously demonstrate the extent to which the subject is part of everyone's daily life. No previous knowledge is required. Elisabeth Busser teaches high school mathematics. Gilles Cohen is a mathematics teacher, and founder of the Fédération Française de Jeux Mathématiques.