Exploring changes in mathematics teachers' envisioning of potential argumentation situations in the classroom.

This study examines changes in teachers' envisioning of potential classroom argumentation situations through experiencing a cycle of: (1) analyzing various tasks' affordances for argumentation, (2) collaboratively analyzing examples of (other) teachers' analyses of those tasks' potential for argumentation, (3) refining initial analyses, and (4) reflection. Analysis of teachers' initial and refined responses revealed changes in the variety of dimensions of argumentation envisioned (e.g., mathematical, social, cognitive) and in the number of teachers categorized in each dimension. The paper provides evidence of the potential of collaborative analysis of authentic teacher responses for teachers' learning of key aspects of argumentation practice. • In the study, the teachers increased their noticing of mathematical tasks potential for argumentation. • The study provides evidence that collaborative analysis of authentic teacher responses supports the teachers' learning. • The study suggests approaches for teacher professional learning for developing expertise in argumentation. [ABSTRACT FROM AUTHOR]