Understanding mathematics teacher's argumentation: considerations during classroom tasks discussion

International audienceThis paper presents the research results whose aim is to understand the mathematics teacher's argumentation during classroom tasks discussion. Aspects of a theoretical stance are used, on the one hand, to show how the teacher's argumentation can be described in the mathematics classroom and, on the other hand, to specify aspects of the discourse in the mathematics classroom. The analysis is illustrated with one episode in a tenth-grade classroom, where the teacher and her students discuss the solution of a task about trigonometric ratios. The results allow recognizing features of the teacher's argumentation features, purposes, and conditions that activate it