Minds On
Unit Rate
Student Success
Think-Pair-Share
Work with a partner, if possible, to compare the two products in the image below.
The first image is a 750 ml container of yogurt with a unit price of $0.02 per ml and a retail price of $15.00.
The second image is a 95 ml container of yogurt with a unit price of $0.05 per ml and a retail price of $4.75.
If possible, with a partner, discuss the following:
How might customers use the information to make an informed decision as to which container of yogurt is the better buy?
Discuss all the clues, such as the retail price per item, how much the item weighs, and the unit price per item.
A grocery store shelf with two different yogurt sizes. The first is a 750 millilitres of yogurt with unit price of 0.02 cents per millilitres. The next is 95 millilitres of yogurt at 0.05 cents per millilitres.
Note to teachers: See your teacher guide for collaboration tools, ideas and suggestions.
Now you are going to learn all about unit price.
In the yogurt question above, the better buy is the yogurt that costs two cents per ml. Unit price tells the customer which yogurt is the better buy because it explains the price per unit.
Action
Calculating unit rate
What is a rate?
A rate is a ratio of two quantities using different units.
For example, if we pay $27.00 for 3 pizzas, we are comparing the unit "dollar" to the other unit "pizza."
This can be expressed as a fraction where the numerator is 27 and the denominator is 3.
What is a unit rate?
When we express a rate as a fraction and the denominator of that fraction is 1, it is a unit rate.
In the pizza example we are using, the unit rate is $9.00 per pizza, or $9.00/pizza.
How do we calculate unit rate?
To find out the unit rate for each pizza, we would need to divide the numerator (27) by the denominator (3). This will give the unit rate, which is $9.00 per pizza.
This is a great skill to know because it allows consumers to decide which is the better deal while they are shopping.
Practicing unit rate
Let’s try practising this concept.
The chef at a breakfast restaurant has run out of syrup for today’s menu. They need enough maple syrup to fill the little containers for the tables. They quickly run out to their local grocery store to pick up a bottle of maple syrup. On the shelf, they decide between two products:
Product A: 1L of maple syrup for $13.97
Product B: 500mL of maple syrup for $9.97
Press ‘Hint’ to access a hint about millilitres versus litres.
1,000ml = 1L
Which product is the better buy? Explain your thinking.
Consolidation
Unit Rate Questions
You now will demonstrate what you have learned by choosing to answer ONE of the two questions below:
Question 1
A group of friends is going to a carnival. The group has $50.00 to spend. The following ticket prices are listed in the booth:
- 15 tickets for $4.68
- 40 tickets for $11.60
Complete the RICE Strategy Organizer in your notebook or using the following fillable and printable document and answer the following questions:
- Which is the better buy?
- What is the maximum number of tickets they can buy with $50.00?
Question 2
A group of grocery store employees is making their fellow employee a chocolate cake. They realize once the cake is made that they have run out of icing, so they run to the store to purchase the icing. There are two different containers of icing to choose from. Both containers are different sizes. They have to make a decision and have $10.00 to spend:
Container #1: 340g for $5.99
Container #2: 170g for $3.50
Complete the RICE Strategy Organizer in your notebook or using the following fillable and printable document and answer the following questions:
- Which is the better buy?
- Are there any other factors the employees could consider about these two containers being different sizes when purchasing the icing or putting the icing on their cake?
Reflection question
Which part of the question do you think you could explain to someone who is trying to solve this problem? Can you help someone to solve this with greater ease? Why? What would you say?
Reflection
As you read through these descriptions, which sentence best describes how you are feeling about your understanding of this learning activity? Press the button that is beside this sentence.
I feel...
Now, record your ideas using a voice recorder, speech-to-text, or writing tool.