Examining the proving processes of pre-service middle school mathematics teachers

Proving is a fundamental skill that pre-service mathematics teachers are expected to develop and to support in their future students. This study aimed to examine the proving processes of pre-service middle school mathematics teachers. To this end, a total of 30 participants were selected through maximum variation sampling from among pre-service teachers who had just been admitted to a middle school mathematics teacher education program and pre-service mathematics teachers at all year levels of the program, with six participants from each level, and the data of this qualitative study were collected through clinical interviews. The data were collected in the context of the concepts of function and number. According to the results of the study, participants at the higher year levels generally showed greater success in constructing the formal-rhetorical part of a proof and in solving its problem-centered part, indicating a cross-year pattern rather than individual longitudinal change. It was also concluded that even when participants in the upper years possessed knowledge of proof methods, either their lack of sufficient conceptual knowledge to solve the problem-centered part or their deficiencies in the use of mathematical language hindered the proving process. Furthermore, it was observed that the participants were unable to use the full range of proof methods; whereas proof by counterexample showed the highest success in the proving process at every level, participants experienced difficulties in the direct proof and proof by contraposition processes. The findings suggest that the formal-rhetorical and problem-centered parts of proof should be addressed explicitly and systematically across all year levels of mathematics teacher education programs.