Assessment in mathematics as a lever to promote students' learning and teachers' professional development

International audienceIn this paper, we are presenting our analytical tools to characterize assessment activities as part of teachers' practice, on a specific mathematical content (algebra). We are also presenting the principles of our collaboration with high school teachers, inside a particular workgroup (LéA), to explain why we came to consider assessment as a potential lever to enhance both the students' learning in mathematics, and the teachers' development. We are presenting a few results on the effects of this collaborative work on teachers' practice when assessing students' learning, and on our means to analyze the students' results throughout the process