In this article, we would like to describe the integration of the temporal dynamics of learning and teaching in three Secondary I mathematics classes. This description is based on observation data gathered from three classes under the responsibility of the same teacher; the first is a group of repeaters, the second, a group of average students and the third, a CHALLENGE class (strong students). On the basis of an analysis of both the temporal organization of lessons and the didactic interactions observed in the classes, our research allows us to differentiate the role that didactic time plays in the workings of the three didactic systems studied.