The importance of cooperative work in order to achieve meaningful learning in mathematic classes during the first two stages of Basic Education motivated doing a qualitative study, based on research-action. Following the suggested steps for this type of methodology, we performed a diagnose to then design and apply strategies based on cooperative work. During the evaluation we were able to see the importance of cooperative work in mathematic classes, aiming to promote motivation, interaction and meaningful learning. In the conclusions we point out as fundamental characteristics to design cooperative strategies: previous knowledge of the students, attention to the four areas of math (arithmetic, algebra, geometry and statistic), the interrelation with the other curricular areas and the incorporation of playful activities.