Lesson 20

How Much in the Group? (optional)

Lesson Purpose

The purpose of this lesson is for students to solve fraction division problems that ask: “How many in one group?”

Lesson Narrative

In this optional lesson, students solve problems where a whole number quantity is a unit fraction of an unknown whole number.  In these situations students may rely on their understanding of the relationship between multiplication and division. For example, if 8 ounces is \(\frac{1}{4}\) of the amount of water in a bottle, students might represent this with a tape diagram:


The tape diagram suggests the equation \(8 = \frac{1}{4} \times {?}\) which students will likely solve by seeing that \({?} = 4 \times 8\). The equation \(8 = \frac{1}{4} \times {?}\) can also be written using division with the equation \({?} \div 4 = 8\).

  • Engagement
  • MLR8

Learning Goals

Teacher Facing

  • Represent and solve problems involving division of a whole number by a unit fraction.

Student Facing

  • Let’s solve more problems involving multiplication and division with fractions.

Required Preparation

CCSS Standards


Lesson Timeline

Warm-up 10 min
Activity 1 20 min
Activity 2 10 min
Activity 3 10 min
Lesson Synthesis 10 min
Cool-down 5 min

Teacher Reflection Questions

What do you love most about math? How are you sharing that joy with your students and encouraging them to think about what they love about math?

Suggested Centers

  • How Close? (1–5), Stage 6: Multiply to 3,000 (Addressing)
  • Rolling for Fractions (3–5), Stage 5: Divide Unit Fractions and Whole Numbers (Addressing)

Print Formatted Materials

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Additional Resources

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PowerPoint Slides

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