A preservice teacher course on the use of cas in school algebra

In this article, a lesson-study-inspired course in mathematics teacher education on the Faroe Islands is studied. The preservice teachers have to conduct four lessons in grade 8, teaching early algebra using a Computer Algebra System (CAS). We analyse the preservice teachers’ practice and knowledge gained during two lessons, combining the instrumental approach and the notions of praxeology and moments from the Anthropological Theory of the Didactic (ATD). The analysis shows that the lesson study structure provides a rich environment for the preservice teachers to develop and formulate didactical knowledge related to the teaching of school algebra with CAS. In addition, most of the developed didactical knowledge echoes that of the literature, both obstacles and opportunities. Further, the combination of ATD and the instrumental approach let us describe and analyse in explicit details the didactical practice and knowledge of the preservice teachers and their development.