Lesson study cultivates teachers' capacity for formative assessment by placing student thinking front and center throughout. Lesson study is a form of professional development in which a team of teachers determines a mathematical focus, collaboratively studies student thinking about the topic, designs a lesson about this content, implements the…

With international exams (PISA and TIMSS) producing results every three or four years, there is near continual talk of East Asian dominance in mathematics education. Beyond the reporting of scores, some studies have compared mathematics teaching in these countries with U.S. instruction. However, researchers are not (usually) grade school math…

In the Netherlands, the "iceberg model," developed by the Freudenthal Institute, has been used to support teacher identification of informal and preformal representations that build students' understanding of formal mathematics. This article offers suggestions on how this model can be used to support professional development,…

This article describes a professional development model in which middle-grades teachers focused on algebraic thinking as part of their participation in a mathematics academy.