Learning Activity

Solving Unit Rate Problems (During)

Overview

In this learning activity, students will learn a strategy for solving unit rate problems from the PBS video. In the accompanying classroom activity, students watch the video and then use grocery store ads to calculate unit rates and compare prices. They share solution strategies and consider ways that unit rates can facilitate making comparisons. To get the most from the activity, students should be comfortable finding equivalent fractions and have had some exposure to the concepts of ratio and unit rate.

Mathematics (2019) Grade(s): 7

MA19.7.1

Calculate unit rates of length, area, and other quantities measured in like or different units that include ratios or fractions.

Unpacked Content

UP:MA19.7.1

Vocabulary

  • Unit rate
  • Ratio
  • Unit
  • Complex fractions

Knowledge

Students know:
  • What a unit rate is and how to calculate it given a relationship between quantities.
  • Quantities compared in ratios are not always whole numbers but can be represented by fractions or decimals.
  • A fraction can be used to represent division.

Skills

Students are able to:
Compute unit rates associated with ratios of fractional
  • lengths.
  • Areas.
  • quantities measured in like or different units.

Understanding

Students understand that:
  • Two measurements that create a unit rate are always different (miles per gallon, dollars per hour)

Phase

During/Explore/Explain
Learning Objectives

Learning Objectives

Students will be able to:

  • solve real-world problems involving finding and comparing unit rates.
  • define ratios and unit rates.

Activity Details

Procedure:

  1. Before: Review the Before Activity by watching the PBS video (10 minutes, whole group) Pause the video at 00:30 (30 seconds). Ask pairs to talk over the solution to the problem posed and jot down their solution strategies.

  2. After a few minutes, resume and finish the video. When it is over, ask students:

    • Did anyone solve the problem the same way as in the video?
    • What other ways did you find to solve the problem?

    Record students’ solution strategies or invite them to come up and do so. Emphasize the variety of possible approaches.

  3. During: Unit Rate in Ads (10 minutes, pairs)
    Distribute the ads. Ask pairs to determine which of their ads offers the best unit price, and record their calculations.
  4. As pairs finish up, pose the following question (tailored to the particular ads):
  5. If you’re going to buy [apples], which unit rate would you find more useful: price per [apple] or the number of [apples] you can buy per [$1]? Why? 
  6. Encourage students to consider which kinds of unit rate calculations might be helpful, which might be less helpful, and why.
  7. Conclusion (5 minutes, whole group)
    Ask for volunteers who worked with different ads to share their solution strategies. Highlight the variety of possible strategies. If no one volunteers, the teacher should offer different ways to work the problems.
Assessment Strategies

Assessment Strategies

The student responses during the class discussion will be used as a formative assessment.

Variation Tips

Activity Extension: Have students look through a wide variety of ads with pricing given as a ratio (e.g., 3 games for $49.99). They should then choose items that they would like to purchase (realistic or not) and determine what unit price they would pay.

Background and Preparation

Background / Preparation

  • The teacher will need to gather grocery store ads with pricing given as a ratio; for instance, 4 apples for $3. Each pair needs two or three such ads for one type of product (e.g., three ads for apples). If possible, provide a variety so that not all pairs use the same ads.
  • The teacher will need to put the students in pairs.
  • The teacher will need to sign up for a free PBS LearningMedia account.
  • To get the most from the activity, students should be comfortable finding equivalent fractions and have had some exposure to the concepts of ratio and unit rate.

Digital Tools / Resources

https://aptv.pbslearningmedia.org/resource/muen-math-rp-unitrate/unit-rate/

Approved Date

Owner (Author)

yvetteakridge
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