Lesson 6
Compose and Decompose Shapes
Warmup: Notice and Wonder: A Picture of Shapes (10 minutes)
Narrative
The purpose of this warmup is to elicit the idea that shapes can be used to compose other shapes, which will be useful when students compose shapes from equalsize shapes in a later activity. While students may notice and wonder many things about this image, identifying the shapes within the picture and noticing how they work together to compose something larger are the important discussion points.
Consider recording the shapes students name as they describe the image on chart paper for students to reference during the lesson. In addition to the vocabulary students used in the previous section (triangle, quadrilateral, hexagon), it may be helpful to review trapezoid and rhombus or add these terms to the chart. It is not necessary to provide a mathematical definition for these terms.
Launch
 Groups of 2
 Display the image.
 “What do you notice? What do you wonder?”
 1 minute: quiet think time
Activity
 “Discuss your thinking with your partner.”
 1 minute: partner discussion
 Share and record responses.
Student Facing
What do you notice? What do you wonder?
Student Response
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Activity Synthesis
 Review the shape names that were recorded.
 “What other shapes do you see in this picture? What other names do you know for these pattern blocks?”
 “Some of you said this looks like a person riding a skateboard.”
 Consider asking:
 “What shapes make up the head and body of the person?”
 “What shapes make up the person's arms?”
 “What shapes make up the skateboard?”
Activity 1: Many Ways to Compose Shapes (15 minutes)
Narrative
The purpose of this activity is for students to compose the same shape in different ways. Students create a butterfly by composing hexagons using different pattern blocks. By composing hexagons with different combinations of shapes, students have the opportunity to see the shape composed of equalsize shapes and combinations of different shapes. Students are encouraged to explain how they composed their hexagons using the geometric language they’ve learned in previous lessons (MP6). For example, “I used 1 trapezoid and 3 triangles to make a hexagon.” Throughout the activity, listen for the ways students notice describe how they can compose a shape from or decompose shape into smaller shapes (MP6).
In the lesson synthesis, students may share many different ways to compose the hexagon, but the focus shifts to hexagons that are composed of equalsize pieces.
Advances: Speaking
Supports accessibility for: Language, Memory
Required Materials
Launch
 Groups of 2
 Give students pattern blocks and a copy of the blackline master.
 Display the pattern block butterfly image.
Activity
 “Mai used pattern blocks to make this design. Work with a partner to make the same design without using any yellow hexagons.”
 “Try to use as many different shape combinations as you can to make each hexagon.”
 “For each hexagon, draw the lines inside the shape to show how you composed it.”
 “Pick one of your hexagons. Use words and numbers to explain how you composed it.”
 10 minutes: partner work time
 Monitor for students who:
 compose a hexagon using equalsize shapes: 2 trapezoids, 6 triangles, or 3 blue rhombuses
 compose hexagons using different shapes
Student Facing
Student Response
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Advancing Student Thinking
 “How do you know these shapes make a hexagon?”
 “How could you use different blocks to make the same shape?”
Activity Synthesis
 Invite previously identified students to display their hexagons. Begin with the examples of hexagons composed of the same shape. Then select students to share other examples of hexagons composed of different shapes.
 If possible, display student hexagons as they share. Keep the hexagons displayed into two groups like the following:
 “You found a lot of different ways to compose a butterfly design without using hexagons. What do you notice about these two groups of hexagons?” (In the first group, they are made using the same shape. 6 triangles, 2 trapezoids, or 3 rhombuses. Each hexagon in the second group is made using more than 1 shape.)
Activity 2: Compose Shapes with Equalsize Pieces (20 minutes)
Narrative
The purpose of this activity is for students to compose shapes with 2, 3, or 4 equalsize shapes. The work of this activity lays the foundation for partitioning shapes into halves, thirds, or fourths.
Students make three different shapes using 2, 3, or 4 pattern blocks of the same shape. They record their compositions on either the triangle or square grid paper. The structure of the grids helps students make sure that each of the parts of their shapes are equal.
Required Materials
Materials to Gather
Materials to Copy
 Centimeter Dot Paper  Standard
 Isometric Dot Paper  Standard
Launch
 Give each student pattern blocks.
 Give students access to triangle and square grid paper.
 Display the 3 shape images.
 “What is the same? What is different?”
 30 seconds: quiet think time
 Share responses.
Activity
 “In this activity, you are going to make shapes that only use the same equalsize shape, like the first and third shapes.”
 “Compose three different shapes using 2, 3, or 4 of the same equalsize shape. Show the outline of each block on the grid paper. Name each shape and explain how you composed it.”
 “You can use the triangle or square grid paper to help you record.”
 As needed, demonstrate drawing the outline and naming the hexagon formed from 6 triangles from the launch on dot or grid paper.
 8 minutes: independent work time
 Monitor for a student who composes a shape out of 2 blocks and one who composes a shape out of 4 blocks.
Student Facing
What is the same? What is different?
 Compose 3 different shapes using 2, 3, or 4 of the same equalsize shape.
 Show the outline of each block on the grid paper.
 Name each shape and explain how you composed it.

I used ________________________________
to compose a _____________________________.

I used ________________________________
to compose a _____________________________.

I used ________________________________
to compose a _____________________________.
Student Response
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Activity Synthesis
 Display selected students’ shapes.
 “Describe how these shapes are composed.” (They used 2 trapezoids to compose a hexagon. They used 4 small squares to compose a larger square.)
Lesson Synthesis
Lesson Synthesis
“Today we thought about how shapes could be made using other shapes. We composed shapes from equalsize smaller shapes.”
“Tell your partner 2 different shapes you made today. Describe what shapes you used to compose your shapes.” (I made a larger square out of 4 smaller squares. I made a hexagon with 2 trapezoids. I composed a pentagon with a square and a triangle.)
Share and record responses.
Cooldown: Look for Equalsize Shapes (5 minutes)
CoolDown
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