Abstract
This paper describes the design and implementation of a training process about proportional reasoning with students of a Master’s Degree in Secondary Education in Spain. The main objective of the experiment is to explore their initial knowledge and to evaluate how competent the participants on analysing relevant aspects of the epistemic facet of the didactic-mathematical knowledge, which are concretized in the recognition of algebrization levels through different solutions to proportionality problems, are. The participants in the experience have been 33 students, with diverse background education profiles, of the course Initiation to the Teaching Innovation and Investigation in Mathematics Education. Among the results, we highlight the students’ limitations and difficulties to identify propositions and procedures and their related arguments. Likewise, the assignment of algebrization levels has also been a complex and difficult task for the participants. Besides, some students have shown deficiencies in the common knowledge of proportionality, which serves as a basis for the didactic-mathematical knowledge of the content. It is concluded that an improvement of the results requires, among other actions, to increase the time allocated to the formative intervention, which will allow extending the number and variety of situations-problems posed, their solutions and discussions.
Proportionality; Teacher’s education; Onto-semiotic approach; Algebrization levels; Epistemic analysis