This study examined the changes that a group of nine Israeli 7th grade mathematics teachers, who collaborated on editing the textbook they used in class, chose to make in the textbook. Data sources included the project website (using a modified wiki-book platform), the group meetings, interviews with the teachers, individual papers written by the…

This study examines how students' opportunities to engage in argumentative activity are shaped by the teacher, the class, and the mathematical topic. It compares the argumentative activity between two classes taught by the same teacher using the same textbook and across two beginning algebra topics--investigating algebraic expressions and…