Better Deal Stations

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Objective

SWBAT: • Use multiplication and division to solve problems involving equivalent rates. • Apply different strategies for explaining comparisons between quantities.

Big Idea

What is the better deal? How do you know? How do stores try to trick you? Students work in groups to determine the better deal.

Do Now

3 minutes

See my Do Now in my Strategy folder that explains my beginning of class routines.

Often, I create do nows that have problems that connect to the task that students will be working on that day.  Here, I want students to review their measurement conversions.  I have added quarts and gallons, which students will need later in the lesson.

Students check their answers and make sure their do now has the correct facts.

Become an informed consumer

5 minutes

I want students to be able to compare deals, but I also want students to be aware of the tricks that some stores use to try to fool them.  The more students know the more they will be able to make informed decisions.  I comparison shop all of the time!  I have to use math to figure out the better deal, and every penny counts.  I also use math to figure out which coupons are better than others.  I want students to connect to this lesson and see how it can help them in their own lives.

If I have extra time, I ask students to share out a time when they compared prices on an item.  How did you get the information?  Was it worth the time and effort?

Better Deal Stations

27 minutes

Notes:

  • Before this lesson, I create groups.  If students are still struggling with decimal operations, I will allow them to use a calculator during this lesson.  They still need to set up and label the rates, but using a calculator will allow them to access the problem.
  • Before the lesson, I set up stations around the room.  Each station has copies of that particular deal.  I will have some duplicate stations, so groups who are ready to move on can move on.

I ask students to share out the strategies they used in the State Fair lesson to figure out the better deal.  I list these strategies on the board so students can reference them later.  I review expectations for the day and students move into groups.  I know that not all groups will complete all stations and this is okay.  The important part is that groups are applying strategies in a systematic way and are developing ways to justify their answers to each other.  I stress to students that they must show their work in order to convince me they have found the better deal.

Students are engaging in MP1: Make sense of problems and persevere in solving them, MP2: Reason abstractly and quantitatively, and MP6: Attend to precision.  

 

As students work, I walk around to monitor student progress.

If students are struggling, I may ask one or more of the following questions:

  • What do you know?
  • What do you need to know?
  • How can we compare two different rates?
  • How will we know which one is the better deal?
  • How should we round our answer?

If students are in need of extension, I may ask one or more of the following questions:

  • What is the unit rate for each product? (There are 2 unit rates, for example price per ounce or number of ounces per dollar.  The price per ounce/pound/gallon is commonly displayed in grocery stores)
  • When might someone knowingly choose the product that is more expensive?
  • A pack of twelve 12-ounce cans of Polar raspberry lime seltzer is $4.99.  How does that compare to the other seltzer prices?

Closure and Ticket to Go

15 minutes

 For Closure I call on groups to share what they found to be the better deal as well as how they figured it out.  I am excited to see what strategies students use.  The Gatorade problem is interesting because when you round your calculation, both products have the same cost per ounce.  What are the advantages of one of the packages of Gatorade over the other?  Each of the deals has interesting questions, so I will let groups decide what they want to talk about.  Students are engaging in MP3: Construct viable arguments and critique the reasoning of others.

After groups share, I talk to students about unit prices.  I show them some of the pictures of the products with their unit prices.  This is a great way to quickly compare deals in the store.  You just have to make sure that the unit prices you are comparing have the same units (not price per pound vs. price per ounce). 

I pass out the Ticket to Go and the HW Better Deal.