While a growing amount of research is devoted to exploring teachers’ practice as they engage in responsive teaching at the elementary school level, less is known about the secondary school level. One particular challenge at the secondary school level is that well-developed learning trajectories of student thinking are uncommon. This study investigates two teachers who, after receiving extensive professional training, both create classroom environments where students’ conceptions serve as a focus of their instruction and who are both able to attend to and interpret the details of student thinking. Notwithstanding these similarities, subtle differences in their classroom instruction result in major differences in outcomes. This session reports on these differences and highlights the important role learning trajectories play in responsive teaching and the professional noticing of students’ mathematical thinking.

Session Type: Poster Session