Effective teachers of mathematics attend and respond to the substance of students' thinking to support formal instruction. This five-year project expands current work on teacher noticing by investigating teacher noticing of children’s multimodally (e.g., gesture, action) expressed “seeds” of algebraic thinking. The project will involve the design and implementation of a video club curriculum in which teachers examine and annotate classroom videos using a video annotation tool (www.anotemos.com). Two cohorts of preservice teachers will engage in the video club curriculum and engage in reflective interviews about their noticing practices. Follow-up classroom observations will be conducted to see how teachers then notice multimodal algebraic thinking in their classrooms.