Pre-service secondary mathematics teachers’ evolution of communally agreed-on criteria for proof

Developing communally agreed-on criteria for proof in a mathematics classroom has been found to empower pre-service secondary mathematics teachers’ (PSMTs’) learning of proof. To date, we do not know how creating class-based criteria for proof throughout a semester-long course with a focus on secondary school mathematics can promote PSMTs’ understanding of proof. In this paper, we reported PSMTs’ evolution of what constitutes proof by comparing their initial and revised classbased criteria for proof and investigating their videotaped lessons and video transcripts. Results indicated that PSMTs perceived mathematical values and norms of what counts as proof in their mathematics classroom community as the semester progressed.