Making Students' Arguments Public
Although this is the first correct reasoning that is presented in the whole class, it is not positioned as correct by the teacher. Rather, it is one more argument to consider about how to determine the perimeter of the 25th figure.
Clip 2a: Jahlil's argument
Clip 2b: Robert's and Amanda's Arguments
Here you'll see Ms. Hauser ask another group to share their method, again without judging it as correct or not. This sets the stage for the discussion that follows.
Listen to mathematics educators Megan Staples and Mark Ellis as they discuss how Ms. Hauser helped Jahlil share his argument with the class and bring it into a public space.
Robert's group's work that he explained in the clip above.
Transcription of student work: Made a line of 25. Then, split them into groups of 4. In each group the perimeter was 18, and there were six groups.