# ﻿How Much for One? (Working with Ratios)

Warmup

Activity #1

Use a Double Line Tool to Find Cost.

In the following activity, we are gong to find the cost of avocados, if 8 avocados cost \$4.

• Use the applet below to show your work for the following questions, if you choose to.

In the following activity, we are gong to find the cost of water bottles, if 12 large bottles cost \$9.

• Use the applet below to show your work for the following questions, if you choose to.

(1.) How many bottles of water can you buy for \$3? Explain your reasoning.

(2.) What is the cost per bottle of water? Explain your reasoning.

(3.) How much would 7 bottles of water cost? Explain your reasoning.

Activity #2

Calculations Involving Ratios.

In the following activity, we are gong to find the cost of bags of chips, if 4 bags cost \$6.

• Use the applet below to show your work for the following questions, if you choose to.

(1.) What is the cost per bag?

(2.) At this rate, how much will 7 bags of chips cost?

In the following activity, we are gong to find the cost of used books, if 5 books cost \$15.

• Use the applet below to show your work for the following questions, if you choose to.

(1.) What is the cost per book?

(2.) At this rate, how many books can you buy for \$21?

Activity #3

Share an Amount in a Given Ratio.

You are probably familiar that the following steps are used in sharing an amount in a given ratio;

1. Add up the ratio to find the total number of parts,
2. Divide the total amount by the number of parts,
3. Multiply by the ratio to find each person’s share,
4. Check these add up to the original amount.

In this activity, you are going to use an applet to explore these steps with a visual display of each step. The starting amount to share is 60, and the ratio; 4:6 is displayed on the sliders. just follow the instructions below to see the various steps.

• Check the first box “show total Ratio Units”. Step 1 above is achieved (the ratios are added up.)
• Check the second box “show value of each unit”. Step 2 above is achieved (the diagram is divided by the total of the ratios.)
• Check the third box “show value for ratio parts”. Step 3 above is achieved (each share is found).
• You can verify that the shares add up. Step 4.
• Now, use the two sliders at the top to choose a different ratio of your choice. (RatioPartOne for the first number in the ratio, and RatioPart2 for the second number in the ratio.) ​
• Keep working with other ratios and different amounts.

Quiz Time