Lesson 4 Build Fractions from Unit Fractions

    • Let’s build other fractions from unit fractions.

Warm-up Number Talk: 3 and Another Factor

Find the value of each expression mentally.

Activity 1 Introduce Secret Fraction

The goal of the game is to be the first to build 2 secret fractions with unit fractions.

  1. Make two stacks: one for secret fractions and one for unit fractions. Place all cards face down.

  2. Each player draws 2 secret fraction cards. These are the fractions you are trying to make with your unit fractions.

  3. On your turn, you can make one of these moves:

    • Pick up 1 unit fraction card.

    • Trade both of your secret fractions for 2 new secret fractions from the stack.

  4. When you have enough unit fractions to make one of your secret fractions, shade your gameboard to represent your secret fraction. Then, pick a new secret fraction.

  5. The first player to make 2 secret fractions wins.

Gameboard
Diagram of game board that shows wholes and fractions of halves, thirds, quarters, sixths, and eighths.

Activity 2 Represent Fraction Situations

Children in Ghana playing a game of Pilolo.

Here are four situations about playing Pilolo and four diagrams. Each diagram represents the length of a street where the game is played.

Represent each situation on a diagram. Be prepared to explain your reasoning.

  1. A student walks the length of the street and hides a rock.

    Diagram. Rectangle.
  2. A student walks the length of the street and hides a penny.

    Diagram. Rectangle.
  3. A student walks the length of the street and hides a stick.

    Diagram. Rectangle.
  4. A student walks the length of the street and hides a penny.

    Diagram. Rectangle.
  5. This diagram represents the location of a hidden stick.

    Diagram. Rectangle partitioned into 2 unequal parts. Larger part shaded.

    About what fraction of the length of the street did the student walk to hide it? Be prepared to explain how you know.

Practice Problem

Problem 1

Jada walks across the street at a stoplight of her way from home to school. Represent the situation on the fraction strip. Explain your reasoning.

Diagram. Rectangle.