"The ""maths through games"" project is part of key action KA-219 ""strategic partnerships - exchange of good practices"".Its purpose was to create mathematical games and didactic proposals for primary school pupils, for the support and success of pupils in the field of mathematics.It gathered 6 schools from France, Belgium, Poland, Portugal, Italy and Slovenia. These primary schools, of very different size (from 50 to more than a 1000 pupils), located in various environments (rural, urban, capital), welcome pupils who do not all benefit from the same opportunities regarding economical, geographical or cultural environment. Based on the observation that the results in mathematics (regarding to the PISA assessments) are low in many countries of the partnership, or in decline for several years, the teachers of the project wanted to boost their practices and provide, by the creation of mathematical games, educational tools and learning situations to improve students' skills in mathematics.An educational tool in the heart of this project, the game, which is a fun, varied, competitive activity, stimulates reflection, hypothesis approaches, research into strategy and efficiency. It has turned out to be an excellent way to easily make students do the systematization work essential for a good integration of the studied concepts and to connect the most fragile students with mathematics learning.The game has also provided teachers with a way to deal with student heterogeneity, whether related to differences in grade levels within age groups or the management of classes with multiple courses, helping teachers to manage diverse entries regarding to multiple intelligences.The game solicits affect in its positive aspect and has a significant impact on the students' investment in the mathematical tasks offered, especially for the most fragile students who regain a positive self-image through success by playing.The games achieved by the 6 partner primary schools over the 3 years of the project fall within the 6 major mathematical areas: calculation, numbers, measurements, geometry, data management, logic. They were created by teachers and their students, tested, shared. The provided games are accompanied by:- their rules, of course,- but also manufacturing instructions allowing everyone to reproduce the games- for teachers, didactic sheets allowing them to appropriate themselves with the approaches connected to the games,- and short videos of pupils experimenting the games during class.The productions have been experienced and used by teachers in their classes but also by families and other educational actors.The international meetings have enabled teachers to enrich their teaching practices through observation, exchange, analysis, sharing and pooling as well as the construction of common evaluation tools.For the students, mobility (learning activities) were major highlights of the project, both in terms of human experience and mathematical practice, which enabled them not only to improve their mathematicalskills by experimentation with games but also to be part of the construction of an identity of student, representative of his school and his country, and as a European citizen. The confrontation of learning methods, sharing, exchanges, challenges have greatly contributed to enriching the lived experience and have been important learning motives, in terms of mathematical skills but also of foreign language skills (English) or in digital technologies."