Mathematics teacher’s specialised knowledge: reflections on the teaching and learning of proportionality

Abstract

This paper presents the initial results of a research project involving a group of teachers in a community of inquiry and reflection on proportional reasoning, starting from the context of the sun shadows. With the aim of understanding how the sharing of ideas and teaching practices can help to make teachers’ professional knowledge visible, open to discussion and, possibly, subject to transformation, the framework of meta-didactical transposition was combined with the model of mathematics teacher’s specialised knowledge. Through the analysis of transcripts of discussions in the community of inquiry, different aspects of teachers’ specialised knowledge on direct proportionality were identified in their discourse. Moreover, the findings show how this knowledge is closely intertwined with their beliefs about the teaching and learning of direct proportionality.