Abstract
The research reported in this article is part of a larger study that examines an initiative to
expand teacher expertise in facilitating mathematical problem solving within the framework of
developing and field-testing pedagogical resources. We focus on one year of the study and report
on the complex process of professional development as teachers move from traditional
pedagogies of teacher explanation of mathematical operations followed by student practice to a
pedagogy of teacher and student exploration of number operations within a problem-solving
environment. We see that, in this initiative, teachers, consultants, and professional developers
explored new mathematical and pedagogical ideas, creating a collective that provided a
supportive environment that served as a model for classroom settings where teachers and
students, in turn, investigated mathematical ideas.