School transitions are particularly challenging for students when it comes to mathematics. Whether moving from elementary to secondary school or from secondary school to college, students have difficulty understanding the new requirements when changing educational levels and this inevitably has consequences (e.g. dropping out, withdrawing from science programs, etc.).

However, students are not the only ones affected by the challenges of transition. In fact, transitions are difficult for teachers as well. Indeed, teachers who work with students arriving from another educational level are faced with students who have either not all seen the same concepts, or have not covered them in the same way. The wide diversity of student preparation for the next level of education and the inability to communicate with colleagues from the previous level pose a major challenge. Some teachers tend to criticize the previous institution for students' lack of preparedness.

The transition from one level to another is first and foremost a transition between different mathematical cultures.

Our research shows the importance of moving away from this rationale of blaming the previous level. Transition problems in mathematics are more complex. Each level of instruction has its own ways of doing and thinking about mathematics. The transition from one level to another is first and foremost a transition between different mathematical cultures.

From this perspective, transitions between levels of mathematics instruction are particularly difficult because they are accompanied by an accumulation of *micro-disruptions *(term borrowed from Praslon, 2000) in the ways of presenting and giving meaning to mathematical objects, in changes to mathematical rules, and in the teaching practices related to mathematics content. A variety of circumstances, specific to each level, shape the ways in which mathematics is done and affect the meaning attached to mathematical objects.

The ARIM research project is based on building a dialogue between mathematics teachers. Through a collective endeavour (involving school staff and our research team), we are seeking to better understand the different ways of doing mathematics at each level (elementary, secondary and college). In doing so, we are asking ourselves what kind of arrangements should be made to 1) foster discussion and exchange between teachers and 2) support students in transitioning from one level to another.

**Main researcher**: Claudia Corriveau, Université Laval

**Original title**: *Projet ARIM [Actions et rapprochements interordres en mathématiques] : processus de rapprochement des pratiques d'enseignement de mathématiques pour favoriser un passage plus harmonieux pour les élèves lors de transitions scolaires*