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Lesson

3rd Grade Math – Area and Perimeter

Clip 9/11: Area and Perimeter Lesson Part 2C

Overview

Robin asks her 3rd-grade students to talk about what they noticed regarding area and perimeter in the work that they did with tiles on the chart paper. One student shares that “the difference is that they all have different sizes.” Some look at the equations themselves, one saying, “I think the area is all the same, and the squares are all different, so the perimeter is different.” A partner restates, “They’re all different shapes and sizes, so it’s different perimeter.” Robin gathers the group’s attention and asks them to reflect on the strategy they used to find the different sizes of the rectangles. One student immediately replies, “Addition!” Robin responds, “Answer as if you’re teaching me.” After discussing, Robin asks groups to share their strategies. One group shares that counting by multiples of five did not work. Robin asks, “What kind of rectangle had the smallest perimeter, and why do you think that is?” She listens to the groups, asking them “Why?” One group shares that it has to do with “shorter distance.” Robin asks the group to talk about the difference between two shapes they created. They identify different numbers of columns.

Teacher Commentary

So, now's the time. “So, what do you think? What are your thoughts?” Looking at every different way possible that you can possibly think a child might figure it out, and they will still throw you for a loop.

Because there have been kids, when they've gotten up and they're solving a problem, and I'm like, “How is this going to work?” because, in my mind, it doesn't work. But actually, when I listen to them, I'm like, “Oh, they taught me something today.”

Little do they know that every time I'm going somewhere, or working with the three teachers that I mentor in their classrooms, I pick up on things that they do. I'm always learning.

Materials & Artifacts