How to Using Decimals, Grid Models, and Fractions to Represent Percent

A percentage is a rate per 100. You can use 10×10 grids to develop a percentage.
To find a percentage of a number, merely multiply.
To convert a decimal into a percentage, multiply by 100 (merely move the decimal point two spaces to the right).
To obtain the percent equivalent, move the decimal point 2 spaces to the right-hand side.

Step-by-Step Guide to Using Decimals, Grid Models, and Fractions to Represent Percent

1. Understand the problem: Read the problem carefully and identify the information provided and the information that needs to be found.
2. Convert the percent to a decimal: Divide the percent by 100 and write it as a decimal. For example, 25% can be written as 0.25.
3. Use the decimal to complete a grid model: Draw a grid with labeled columns and rows to represent the given and unknown information. Fill in the known values, such as the decimal and the whole, into the grid.
4. Write the equation: Write the equation using the information provided in the grid. For example, if the problem states that an item is 25% off, the equation is: part = (decimal) * whole
5. Solve the equation: Substitute the known values into the equation and solve for the unknown value.
6. Convert the decimal to a fraction: Write the decimal as a fraction with a denominator of 100. For example, 0.25 can be written as 25/100.
7. Simplify the fraction: Reduce the fraction to its simplest form. For example, 25/100 can be simplified to 1/4.
8. Write the final answer in a complete sentence: Use the simplified fraction or decimal to express the final answer.

Using Decimals, Grid Models, and Fractions to Represent Percent – Examples 1

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

1. We are given that the shirt is on sale for 25% off and the original price is $50.
2. Convert the percent to a decimal: 25% can be written as 0.25
3. Draw a grid model with labeled columns and rows: Original price, discount and sale price columns, and whole, decimal and part rows.
4. Write the equation: part = (decimal) * whole
5. Fill in the grid:

Original price $50 Discount 0.25 Sale price x

6. Solve the equation: part = (decimal) * whole => x = 0.25 * 50 => x = 12.5
7. Check your work: $50 – $12.5 = $37.5, which is the price of the shirt after a 25% discount.
8. The sale price of the shirt is $37.5 or 25/100 of the original price.

It’s worth noting that this is just one way to use decimals, grid models, and fractions to represent percent, and you can use different methods depending on the information provided in the problem

Using Decimals, Grid Models, and Fractions to Represent Percent – Examples 2

Show 49% on the grade and write as a fraction and decimal.
Solution:
Shade 49 of the 100 squares to represent 49% of the grid model.
As a fraction, 49% is equivalent to \(\frac{49}{100}\).
As a decimal, \(49÷100=0.49\)

Using Decimals, Grid Models, and Fractions to Represent Percent – Examples 3

Show 72% on the grade and write as a fraction and decimal.
Solution:

Shade 72 of the 100 squares to represent 72% of the grid model.
As a fraction, 72% is equivalent to \(\frac{72}{100}\).
As a decimal, \(72÷100=0.72\)
Divide the numerator and denominator by 4 to write the in the simplest form.
\(\frac{72}{100}=\frac{72÷4}{100÷4}=\frac{18}{25}\)