Lesson 8 Are All Pieces Created Equal?

    • Let’s make halves, thirds, and fourths in different ways.

Warm-up Number Talk: 5 Ones

Find the value of each expression mentally.

Activity 1 Make Quarters and Halves

Lin wanted to partition this square into quarters. She started by splitting the square into halves.

Diagram. Square partitioned into two equal parts. 

After she drew the first line, she tried 3 different ways to make fourths.

  1. Which of these shows fourths or quarters? Explain and share with your partner.

    A
    Diagram. Square partitioned into four unequal parts.
    B
    Diagram. Square partitioned into four equal parts.
    C
    Diagram. Square partitioned into 4 unequal parts.
  2. Name the shaded piece.

    A
    Diagram. Square partitioned into four equal parts. One part shaded.

    Shape A has a shaded.

    B
    Diagram. Square partitioned into four equal parts. One part shaded.

    Shape B has a shaded.

  3. Show 2 different ways to partition the rectangle into quarters or fourths. Shade in a fourth of each rectangle.

    Rectangle.
    Rectangle.
  4. Show 2 different ways to partition the square into halves.
    Shade in a half of each square.

    Square.
    Square.

Activity 2 Make Equal Pieces

  1. Lin, Mai, and Andre were asked to shade in a third of a shape.

    Lin

    Diagram. Rectangle partitioned into 3 equal parts. One part shaded.

    Mai

    Diagram. Rectangle partitioned into three equal parts, one part shaded.

    Andre

    Diagram. Circle partitioned into thirds. One third shaded.

    Do all their shapes show a third shaded? Explain and share with a partner.

  2. Partition the rectangle into thirds and shade a third of the shape.

    Rectangle.
  3. Diego’s dad made 2 square pans of cornbread and sliced them up for the family.

    Diego’s Brother

    Diagram. Square partitioned into four equal parts. One part shaded.

    Diego’s

    Diagram. Square partitioned into 4 equal parts. One part shaded.

    Diego’s little brother was upset because he thought his piece of cornbread was smaller than Diego’s. What would you tell him?

Practice Problem

Problem 1

Diego cut a square into two equal pieces and then cut one of the pieces into two equal pieces. He says the shaded part is a third of the square. Do you agree with Diego? Explain your reasoning.

Diagram. Square partitioned into 3 unequal parts, 1 part shaded.