The design of textbooks and their influence on students’ understanding of ‘proof’ in lower secondary school

In this paper we report on our analysis of textbooks commonly used for teaching students about proof in geometry in lower secondary school in Japan. From our analysis we found that, as expected from the curriculum specification, deductive reasoning is prominent in Japanese textbooks. Yet the way that proof and proving is presented in these textbooks shows geometry as a very formal subject for study, one that omits to illustrate convincingly for students the difference between formal proof and experimental verification. As such, we argue that an improvement in textbook design is likely to involve providing students with more effective instructional activities so that they appreciate more fully the notion of ‘generality of proof’