Unit 4, Lesson 11
Using an Algorithm to Divide Fractions
Grade 6
Preparation
Lesson Narrative
In this lesson, students complete the process of developing a general algorithm for dividing a fraction by a fraction.
First, students calculate quotients using the steps they observed previously when dividing a number by a fraction—multiply the number by the denominator of the fraction and divide by the numerator. They compare the results to quotients found by reasoning with a tape diagram and verify that the two methods produce the same quotient. They sum up the steps as an algorithm: To divide a number
With an additional strategy at their disposal, students practice calculating quotients involving a wider variety of numbers (whole numbers and fractions). They begin to see the flexibility and efficiency of the algorithm, especially when it is impractical to reason about the division in terms of equal-size groups, with or without using diagrams.
- Coordinate (orally) different strategies for dividing by a fraction.
- Find the quotient of two fractions, and explain (orally, in writing, and using other representations) the solution method.
- Generalize a process for dividing a number
by a fraction , and justify (orally) why it can expressed as .
Required Materials
Activity 2
Required Preparation
Activity 2
For the digital version of the activity, acquire devices that can run the applet.
Have a correction or suggestion?
Tell us about a typo, a broken link, or an improvement you’d like to see. We read every submission but can’t reply.
Have a question or need support instead? Visit our Contact Us page to reach our team.