## Launch the Lesson: What do you shop for?

### Step 1:

• What’s the best part about going grocery shopping?
• Have you ever gone to the store to buy snacks?
• Did you consider the prices of the snacks you chose?
• What kind of snacks do you have in your lunchbox or at home?

Then tell the students that they are going to play a game called Find the Better Deal

### Step 2:

Divide students into predetermined groups. They will play as a group, but every student must show their own work on the worksheet.

Tell the students that they will learn how to find the unit rate, and use it to compare prices.   If they can find the better deal, they can win some of the snacks!

### Step 3:

Write the word RATE on the board.  Have students write it in their notebooks.  Ask the students to think about the word rate and what they think it means.  Have them think about the following questions and write their thoughts under the word RATE in their notebooks.

• What is rate?
• What does it mean?
• What contexts have you used or heard the word rate?

Give students time to write down some ideas.  Then give a few minutes for them to discuss their ideas with their partner or group.  Students should already have experience with what a ratio is and how to write it.

Supplement their ideas with other examples of rates if students didn’t come up with them on their own:  heartbeats per second, miles per hour, cost per pound,  3 items for a dollar, shots per game, miles per gallon, steps per minute, price per pound, price per person.

Emphasize that with rates and ratios, we should always label each number with the correct units.

Define RATE as a special type of ratio that compares 2 different units.  Review the definition of a ratio as a comparison of two amounts, and remind students that it can be written in three ways.  Explain that we usually use the fraction form to show rates and  help find unit rate.

Give this Unit Rate Example:

• If the ratio of pencils to pens is 8 to 2.
• That means for every 8 pencils, we have 2 pens.
• This can be written as 8 to 2, 8:2, or 8/2.
• Ratio as a fraction can help us find unit rate.

Guide the students towards rates that have to do with prices.  Help them make a connection or think about rates in terms of shopping.

You can ask the students if they have ever seen the signs in the store that say “Two for a dollar”, or “3 packs for \$12.00”, or even “Buy one get one free” ?  Explain that these are rates, but they don’t always say how much one item costs.   By finding unit rate, the costs are easier to compare.

## Unit Rate Practice:

Ask students to practice finding the unit rate, where it ends up being less than a dollar.  A good example to show this is with fruit.  Describe that someone might buy 12 ounces of blueberries for \$2.94.  If you have a photo or pint of blueberries, you can show it so students have a good idea of sizes. Ask students to find out what the unit price is, or the cost per ounce of blueberries.

The RATE is

Cost Comparisons Worksheets as follows:

• Write the correct rate for each
• Label the units
• Show their division work
• Write the unit rate for each
• Compare
• Decide which is the better buy and explain their reasoning

After working through the example, send groups of students to each snack station.  You can split up the groups and have them rotate through all of the snacks, or the groups can travel together.  Just make sure that the students are evenly distributed throughout the room and there are enough snack samples to visit.

Remind the students that they need to record their data and come back together to discuss their ideas about which is the better deal.

Don’t forget to tell your students that if they find the better deal, they get to win the snack to eat!

## Reflecting on the Unit Rate Activity

Have each group write and share about which is the better buy.  Groups should briefly present their data and reasoning to the class.

Talk about why stores have different unit rates for different sizes.  Many times, the larger size has a higher price, but it has a lower unit rate.  Why is this?

Also think about the benefits of buying the smaller size, even if it has a higher unit rate.  The final overall price is often less, maybe the customer only has 5 dollars and can’t buy the larger size.  Even if the large box of pretzels has the smaller unit rate, maybe someone can’t eat it all before it goes stale.

### Help Students Think About the Cost of Convenience

Ask: Can you pack the large bucket of pretzels in your lunch box?   Why do small snack packs cost more per ounce and have a higher unit rate?

I have often had great discussions with these questions.  It’s amazing how many ideas and explanations the students come up with.  They have ideas about the snack packs needing more packaging material, or that they can easily fit in a lunchbox etc…   Some talk about large families versus smaller families, or ways to share and save money.  Others talk about how they like the packaging or just want their own bag.  Unit price helps people find the best cost per ounce, but sometimes, the lower overall price or size is a factor as well.

All of these conversations help students realize the real world application of the math skill of finding rates!

## Extensions: Unit Rate

Here are some fun ways to extend the learning of this lesson:

1. Play the game with a budget.  Students only have a certain amount of money.  Which snacks do they buy?  Can they buy some of each snack?
2. Tell students to go to the store and take pictures or record prices of different sizes.  They can compare prices and sizes.  Ask: What do you notice?  Did you know that stores are required to list the unit price as well as the price of the item.  Can you find the unit price?  How does it look different than the price that you pay? Did you know that some stores put the higher unit rate items at eye level, and the better buys on the bottom shelf or top shelf?  Why?  Look closely at the cereal aisle and see where the best priced items are.
3. In class or at home, students can go online and compare prices.  They can choose their own items to compare and share with the class.  Some good items to compare include:  snacks, cereal, yogurt, toilet paper, dog biscuits, laundry detergent.

## FREE Unit Rate Worksheets and Resources

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## Unit Rate Worksheets 6th Grade and Resources

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