Lesson 9

Composing and Decomposing Shapes

Est. Class Sessions: 1
X

Mathematical Standards

2.G.A
Reason with shapes and their attributes. (2.G.A.1)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP5.
Use appropriate tools strategically.
MP7.
Look for and make use of structure.

Students use pattern blocks to fill in the outlines of polygons based on the pattern blocks. As they use the pattern blocks to compose the shapes, they learn the attributes of more obscure shapes.

Content in this Lesson

  • Composing and decomposing shapes into smaller shapes [E6].
  • Identifying and describing 2-dimensional shapes based on their attributes
    (e.g., square corners, number of sides, number of angles, number of parallel sides) [E1].
  • Choosing and using good tools to solve a problem [MPE2].

Daily Practice and Problems Y–Z

Y. Subtraction Facts Quiz: Group E

Z. Comparison

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

pattern block set (4 yellow hexagons, 24 green triangles, 16 brown trapezoids, 12 blue rhombuses, 8 red trapezoids,
    5 orange squares, 12 purple triangles, 8 tan rhombuses) from Lesson 8

Materials for the Teacher

Display of Fill in the Shapes (Student Activity Book) Pages 691–694
Unit 13 Assessment Record
Math Facts Class Record
Display pattern block set

Materials Preparation

Prepare Optional Additional Targeted Practice. Make several copies of the Fill in the Shapes pages from the Student Activity Book. Place the copies and sets of pattern blocks in a center. Allow students more time to use the pattern blocks to compose shapes.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed
Ship Shape
with Feedback Box
Student Activity Book
Pages 695–696
E1. 
Identify, describe, sort, and draw 2-dimensional shapes based on their attributes (e.g., square corners, number of sides, number of angles, number of parallel sides).
E6. 
Compose and decompose shapes into smaller shapes.
MPE2. 
Find a strategy. I choose good tools and an efficient strategy for solving the problem.
DPP Item Y
Subtraction Facts Quiz: Group E
Teacher Guide - digital
E11. 
Determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts in Group E.