This video features a second grade lesson designed to support students as they explore how to represent and solve a word problem when the subtrahend is unknown (54 – ___ = 23).  Students share different strategies and engage in a classroom discussion that surfaces how students can use a diagram to write other math sentences they can solve more easily. This work is part of a school-wide Lesson Study effort focused on building TTP classroom routines.

Additional video features post-lesson discussion commentary by Akihiko Takahashi.

A document outlining the planning team’s research theme, background and research on the content and standards, unit/lesson goals, and unit/lesson plan accompanies the video.