Argumentative activity in different beginning algebra classes and topics

This study compares students’ opportunities to engage in argumentative activity between two classes taught by the same teacher and across two topics in beginning algebra: forming and investigating algebraic expressions and equivalence of algebraic expressions. The study comprises two case studies, in which each teacher taught two 7th grade classes. All four classes used the same textbook. Analysis of classroom videotapes revealed that the opportunities to engage in argumentative activity related to forming and investigating algebraic expressions were similar in each teacher's two classes. By contrast, substantial differences were found between one teacher's classes with regard to the opportunities to engage in argumentative activity related to equivalence of algebraic expressions. The discussion highlights the contribution of the topic, the
teacher, and the class to shaping argumentative activity.