On the effect of using different phrasings in proving tasks

International audience; The research presented in this paper is about the question, if and how the phrasing of a proving task influences students’ proof productions. In our study, 381 first-year preservice teachers were asked to work on a proof questionnaire involving two proving tasks, where the phrasings “prove that”, “show that”, “reason”, and “explain” were used alternatively. Students’ proof productions were analyzed concerning the kind of reasoning, the use of algebraic variables and the number of words used. While we found statistically significant differences in the proof productions for the easier first task, there were no remarkable differences in the case of the harder second task.