ABSTRACT:Abstract(#br)The 1960s were characterized by a wide range of activities aimed at assisting the actual implementation of modern mathematics into the classroom: experimentation with different target groups, related to the development of new curricula, and large-scale programs of teacher re-education. After a first experiment, Georges Papy, a professor of algebra, was consulted, his task being to promote the quality of the experimental actions. Papy engaged himself completely and soon became the ar... 更多KEYWORDS:Belgian experiments; Belgian Centre for Mathematics Pedagogy; Days of Arlon; Emma Castelnuovo; Frédérique Lenger; Georges Papy; Kindergarten teachers; Lucie Libois; Madeleine Lepropre; Minicomputer; Modern mathematics; Paul Libois; Teacher recycling; Teacher re-education; Teacher training;