Connections between Didactic Decisions and Didactic Transposition in the Practice of Mathematics Teachers

This study analyzes the relationship between a mathematics teacher’s didactic decisions and the process of didactic transposition in a first-year high school class. The methodological approach is qualitative, with data collected through classroom observations and interviews. Grounded in French-influenced Mathematics Didactics, particularly in the teacher’s level of activity, the study explores how external, epistemic, and didactic history factors shape the teacher’s choices and the process of didactic transposition. The results show that teaching undergoes continuous modifications, impacted by unforeseen circumstances and classroom interactions. The conclusions highlight that the teacher’s didactic decisions and didactic transposition complement each other, contributing to the organization of school knowledge.