Using Strip Models to Solve Percentage Problems

A strip model is a visual representation that can be used to understand and solve problems involving percentages.

Step-by-step guide to using strip models to solve percentage problems

Here’s a step-by-step guide to using strip models to solve percentage problems:

1. Understand the problem: Read the problem carefully and identify the information provided and the information that needs to be found.
2. Draw a strip model: Draw a strip divided into equal parts, with each part representing a certain percentage. The strip can be divided into 100 equal parts, with each part representing 1%.
3. Identify the whole: Identify the total amount or quantity that the percent represents.
4. Shade in the appropriate number of parts: Shade in the number of parts that represent the percent. For example, if the problem states that an item is 20% off, shade in 20 parts of the strip.
5. Label the shaded parts: Label the shaded parts with the percent or fraction that they represent.
6. Use the strip model to find the part or whole: Use the strip model to find the part or whole by counting the number of shaded parts or the number of unshaded parts and multiplying by the whole.
7. Write the final answer in a complete sentence: Use the information from the strip model to express the final answer.

Using Strip Models to Solve Percentage Problems – Examples 1

A shirt is on sale for 25% off. The original price of the shirt is $50. What is the sale price of the shirt?

Solution:

1. We are given that the shirt is on sale for 25% off and the original price is $50.
2. Draw a strip divided into 100 equal parts.
3. Identify the whole: The original price is $50.
4. Shade in 25 parts of the strip
5. Label the shaded parts: 25%
6. Use the strip model to find the part or whole: 25% of $50 is $12.5
7. The sale price of the shirt is $50 – $12.5 = $37.5.

It’s worth noting that this is just one way to use strip models to solve percentage problems, and you can use different models depending on the information provided in the problem.

Using Strip Models to Solve Percentage Problems – Examples 2

The restaurant has 125 tables. If 50 of them are reserved, what percentage of them are reserved? Use a strip model to show.
Solution:
The total tables are 125 and the reserved tables are 50.
Since 50 is \(\frac{2}{5}\) of 125, divide the strips model into 5 parts.
Divide 100% by 5 to know the percent of each part of 125.
So, 50 reserved tables are equal to 40%.

Using Strip Models to Solve Percentage Problems – Examples 3

60% of the 30 books on the shelves are new. How many of the books on the shelves are new? Use a strip model to show.
Solution:
Step 1: The total number of books is 30 and new books are 60%. Since 60% is \(\frac{6}{10}\) of 100%, divide the strip model into 10 parts.
Step 2: To find the number of each part of the percentage, divide 30 by 10. It is 3.
Step 3: To find 60% of the new books, multiply the 6 parts of the strip model by 3 in each part. \(6×3=18\). So, the new books are equal to 18.