Lesson study, especially when conducted with support from targeted resources, is often identified as a potentially effective means to support teacher learning. In this study, 80 school-based teams of educators, representing 80 classrooms of third- or fourth-grade students in the US, were randomly assigned to one of four conditions: lesson study…

Mathematics teacher professional-development (PD) programs based on Cognitively Guided Instruction (CGI) have been developed and implemented with tens of thousands of elementary mathematics teachers worldwide since the 1980s. Starting with a focus on addition and subtraction on whole numbers in the first CGI PD program, the content of these…

Contemporary state math standards emphasize that students must demonstrate an understanding of the mathematical ideas underlying the computations that have typically been the core of the elementary school math curriculum. The standards have put an increased emphasis on the study of fractions in upper elementary grades, which are the years during…