Abstract

The implementation of a new national curriculum was one of many strategies included in the Chilean educational reform begun in 1990. In mathematics this updating emphasized the mathematical reasoning and incorporated a constructivist teaching orientation, among other issues. This article presents findings from a video-based study that examines mathematical reasoning and constructivist teaching orientation in three-lesson units about the Pythagorean Theorem. The sample comprises 21 7th grade classes, their teachers and correspondent 784 pupils. The results show that the teachers report a high agreement with constructivist teaching orientation when asked in a questionnaire, but according to the videotaped lessons their teaching correspond rather to a receptive orientation. Regarding mathematical reasoning, the majority of the teachers introduced the Pythagorean Theorem by means of an inquiry activity, failing in their contribution to develop of mathematical reasoning.