9 Informal prerequisites for informal proofs

Abstract: Reasoning and proof play an important role in the mathematics classroom. However, prerequisites for the learning of mathematical reasoning and proof, such as logical compe-tence or the understanding of concepts and proofs, are rarely taught explicitly. In an empirical survey with 106 students in grade 8 we investigated students ’ declarative and methodologi-cal knowledge related to some of these prerequisites. The results show that there are certain deficits which make it difficult for students to learn reasoning and proof. Kurzreferat: Beweisen und Begründen sind wichtige Ziele des Mathematikunterrichts. Das Erlernen von mathematische