Reflection: Trust and Respect Strategies for Decomposing 2-D Figures - Section 1: Warm-Up: Area Decomposition


This is one of my favorite Warm-Ups of the school year because there are so many ways students can attack the problem.  The whole-class conversation is rich because there is no one right answer.  This is the kind of problem that forces students to see the answer is the least important part of the problem since the goal is to have a strategy for how to think about decomposing a 2-D shape, not to calculate an area.

I made sure to circulate the room as students worked on the warm-up to get a sense of the strategies that emerged.  Making time to observe students working gave me a sense of who I might call on to share out in the whole class discussion.  By inviting several students to share their work under the document camera and pausing to check in—“who else thought of this problem this way?”—I validated common approaches while showing the class there were still other approaches in the class.  

Something I decided to do this year was to ask students “what surprised you in talking about this warm-up?”  This was the best part of the discussion because students were able to assign status to their peers, praising them for a novel approach they hadn’t before considered and telling them how their strategy created connections and made something “click” for them.    

  Breaking it Down
  Trust and Respect: Breaking it Down
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Strategies for Decomposing 2-D Figures

Unit 10: Geometric Measurement and Dimension
Lesson 4 of 14

Objective: Students will be able to decompose 2-D figures to strategically calculate area.

Big Idea: Through small group and whole class discussion, students will be able to make connections between multiple ways of viewing composite areas and shaded areas of circles.

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2 teachers like this lesson
Math, Geometry, Measurement, modeling, complex, compound figure, decomposition, area measurement, space, shapes
  60 minutes
area application sample resized
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