The role of visualisation and argumentation in the knowledge of prospective elementary school teachers

Argumentation and visualisation are relevant processes in mathematical activity. The aim of this paper is to describe the mathematical knowledge of a group of prospective primary school teachers when they engage in argumentation situations through visual processes. A professional task is designed and implemented with 138 prospective teachers. The notion of epistemic configuration of the onto-semiotic approach and the types of validation are used as tools of analysis. It is found that future teachers recognise the potential of the visualisation process, but most of them are at a low level of generality, where mathematical practices and mechanical procedures prevail, not being able to establish adequate validation criteria.