Investigation of Nonverbal Proof Skills of Preservice Mathematics Teachers’: A Case Study

The importance of both proof and visualization has been frequently emphasized in mathematics education. Visual proof or nonverbal proofs are defined as diagrams or illustrations that help us to see why a mathematical expression is correct, and how to begin to prove the accuracy of this statement. The aim of this research is to examine nonverbal proof skills of preservice mathematics teachers. The study was carried out with case studies, one of the qualitative research designs. The participants of the study consisted of 53 preservice mathematics teachers at a state university in Central Anatolia, Turkey. The data were collected with a sample of three nonverbal proof samples directed to preservice teachers. The analysis of the data classified the preservice teachers’ responses according to their similarities and differences. The findings showed that preservice teachers generally associate images with geometric figures. In addition, it was also seen that those who saw the visual relationship between the given visual and mathematical expression used it to show the expression as correct instead of proofing the visual.