Targeted Skill: Ratios

CCSS.MATH.CONTENT.6.RP.A.3 Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations.

CCSS.MATH.CONTENT.7.RP.A.1 Compute unit rates associated with ratios of fractions, including ratios of lengths, areas and other quantities measured in like or different units. For example, if a person walks 1/2 mile in each 1/4 hour, compute the unit rate as the complex fraction 1/2 / 1/4 miles per hour, equivalently 2 miles per hour.

CCSS.MATH.CONTENT.7.RP.A.2 Recognize and represent proportional relationships between quantities.

Climate Change Connection

Food waste is a concerning contributor to climate change, and one often not talked about. Students will learn about food waste contributions to climate change and ways to decrease the amount of food being thrown away each year. Students complete the Food Waste Ratios worksheet and can extend the activity by creating a list of ways they feel they might be able to reduce food waste in their school or homes. Consider exploring these lessons about food waste:

• Combating Food Waste
• Food and Farming
• Food Waste Lesson

Teaching Tips

• Students can watch the following videos:

Food Waste Causes Climate Change, Here’s How We Stop It

Food Waste is the World’s Dumbest Problem

• Students discuss their own observations regarding food waste. Suggested prompts include: Why do you think there is so much food waste? What are some ways you personally contribute to food waste, and how could you reduce it? What challenges might people face when trying to waste less food? How can small changes in our daily habits help reduce food waste on a larger scale?
• Students discuss the connection between food waste and climate change impacts. Suggested prompts include: How do you think food waste affects the environment, including land, water, and air? How could reducing food waste help slow down climate change and protect the planet for future generations?
• Some students may experience food insecurity at home, impacting their perspectives on food waste. It's important to approach this topic with sensitivity, acknowledging that access to food varies and creating a space for respectful and empathetic discussions.
• To extend this activity, have students write a list of ways they feel they could help reduce food waste in their home or at school.

A serving of cooked rice requires a 1:2 ratio of uncooked rice to water. If a serving size for one person is 1/4 cup of rice, how much uncooked rice and water do you need to make rice for your family of five people without wasting any?

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Rice: 5 x ¼ cup = 5/4 cups = 1 ¼ cups of uncooked rice

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Water: 5 x ½ cup = 5/2 cups = 2 ½ cups of water

You are making pasta for yourself. The instructions say to use the whole box of pasta (4 cups of pasta) and 6 cups of water to cook. You know you can’t eat the whole box of pasta, in fact, you will feel full after eating 1 cup of pasta. What is the ratio of pasta to water, and how much water do you need to prepare one cup of pasta?

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The ratio is 4:6 (alternatively 1:1.5)

You will need 1.5 cups of water to prepare a cup of pasta.

A soup recipe uses a ratio of 1:1:2:3. It calls for 1 cup of chopped onion, 1 cup of chopped carrot, 2 cups of chopped potato, and 3 cups of broth. You are having company over tonight and want to double the recipe, how much of each ingredient will you need?

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Onion: 1 cup x 2 = 2 cups of onion

Carrot: 1 cup x 2 = 2 cups of carrot

Potato: 2 cups x 2 = 4 cups of potato

Broth: 3 cupsx 2 = 6 cups of broth

You want to make a salad dressing for you and a friend. The recipe calls for 4 tablespoons of lemon juice, 7 tablespoons of olive oil, and 2 tablespoon of vinegar for a total of 13 tablespoons of dressing. A serving size of vinaigrette salad dressing is 2 tablespoons per person. If you want to make just enough dressing for you both, how much of each ingredient do you need?

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Calculate the total dressing needed:

2 people x 2 tablespoons per person = 4 tablespoons of salad dressing

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Calculate the fraction of the original recipe: 4 tablespoons = 4/13

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Calculate the amount of each ingredient:

Lemon juice: 4 tablespoons x 4/13 = 16/13 or 1 3/13

Olive oil: 7 tablespoons x 4/13 = 28/13 or 2 2/13

Vinegar: 2 tablespoon of vinegar x 4/13 = 8/13

Authors

Lisa Greenwood, Mallory Swafford

Scientist Reviewer

Archibong Akpan, PhD

Image Resources

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