RT Journal Article T1 The MTSK model as a tool for designing tasks for teacher education A1 Climent Rodríguez, Nuria A1 Contreras González, Luis Carlos A1 Montes Navarro, Miguel Ángel A1 Ribeiro, Miguel K1 Educación matemática K1 Formación de profesores K1 Tareas AB This paper studies the knowledge developed by a group of sixty-two pre-service primary teachers during a training session on the definition of a polygon and the mathematical practice of defining. We explore the knowledge developed by pre-service teachers when they carry out a series of training tasks oriented around the practice of defining with primary pupils, within the theoretical framework of the Mathematics Teachers’ Specialised Knowledge model, and using videos of an authentic lesson as prompt. Data were collected by means of video recordings of the implementation of the training tasks, in conjunction with the pre-service teachers’ own written observations as they watched the recorded lesson. A content analysis was carried out on the collected data using the Mathematics Teachers’ Specialised Knowledge model. The results highlight the way in which knowledge of the mathematical practice of defining is constructed, along with the mathematical objects involved in this practice, and pedagogical aspects of defining with young pupils. They also illustrate how a sequence of tasks oriented around a model of teachers’ knowledge can contribute to the development of this knowledge in initial training programmes, and more especially provide orientation about the training of pre-service teachers in the mathematical practice of defining. PB Springer SN 1863-9704 (electrónico) SN 1863-9690 YR 2024 FD 2024-07 LK https://hdl.handle.net/10272/24770 UL https://hdl.handle.net/10272/24770 LA eng NO Climent, N., Contreras, L.C., Montes, M. et al. The MTSK model as a tool for designing tasks for teacher education. ZDM Mathematics Education 56, 1123–1135 (2024). https://doi.org/10.1007/s11858-024-01605-8 NO Project PID2021-122180OB-I00 (Government of Spain). Project ProyExcel_00297 (Andalusian Government). COIDESO research centre (University of Huelva). DESYM (HUM-168). MTSK network, sponsorized by the AUIP DS Repositorio Institucional de la Universidad de Huelva RD 31 may 2026