Resumen

Background: mathematical reasoning is fundamental for mathematics learning from the first years of schooling. It is a challenge for students and teachers, so it is relevant to deepen ways to develop this ability with the prospective teachers. Objectives: identify the challenges in supervised practice with a view to developing students’ mathematical reasoning, seeking to answer the following question: what challenges do prospective teachers face in planning and exploring tasks that promote mathematical reasoning? Design: it is based on a formative experiment and follows an interpretive methodology. Setting and participants: this experiment was conducted during 13 sessions of the curricular unit (CU) Didactics of Mathematics of the 2nd year of the master’s course in Pre-School Education and Teaching of the 1st Cycle of Basic Education, in a class of 25 students. The participants were four students - two pairs in teaching practice- whose selection followed the following criteria: not having any of the researchers as teaching practice supervisors and regularly intervening in class. Data collection and analysis: the data were collected through participant observation of the CU classes, interviews, and document collection. Results: students face more challenges associated with mathematical reasoning during monitoring phases of the exploration of the tasks and their final discussion. Conclusions: these results point to the need for initial training programs to prioritise activities that support prospective teachers in the understanding of mathematical reasoning processes and that involve them in the planning of tasks and analysing practical exploration that will enhance their development.