In this text we present the main results of a research project whose aim was to investigate teaching and learning problems in Geometry, faced by public school teachers and their pupils from 5th to 8 th grade. We intend to concentrate our discussion on methodological procedures, theoretical concepts and main results, focusing our analysis on three aspects: first, the origin of problems related to the teaching and learning of Geometry; second, the courses of action adopted to confront some of these problems; and third, changes in teachers' concepts and practices.
teaching and learning; geometry; teacher development; changes in pedagogical practices