We used a situative perspective to examine teachers' perceptions of a professional development intervention that integrated lesson study, video clubs, and animation discussions. The analysis of interviews with the five geometry teachers who participated in the intervention during two consecutive years showed three characteristics of professional…

This article describes a part of a large scale study which helped to gain understanding of the high school mathematics teachers' belief about proof. There is obvious disconnect between general beliefs and high school teachers' conceptions about proof as central element of mathematics and mathematics education. A total of 374 mathematics teachers…