Clip 10/11: Area and Perimeter Lesson Part 2D

Overview

Robin asks her students what kind of rectangle had the largest perimeter. Groups eagerly discuss: “This one’s the greater one, this one has 30, this one has 24, and 40 is the more greater one, because it’s greater than all the others.”

Robin asks groups to share their strategies: “Most of the outside is used, and the inside isn’t even touched.” Robin summarizes: “One was shorter, and one was longer. What do you guys think about that?”

She closes the lesson by asking students to appreciate their partners for the “fantastic job” they did, and the students give each other a high five.

Teacher Commentary

Something that was interesting is when we were talking about the perimeter, there was one group that noticed on the shape that had the larger perimeter, they counted every single square versus the shape that had the smaller perimeter. They noticed that the squares that were on the inside, they didn't need to count those squares — that that was for the area and not the outside of the perimeter.