Percents and decimals are very similar forms, so everything you know about decimals carries over when you're working with percents. All you need to do is convert your percent to a decimal, and you're good to go.

To change a whole-number percent to a decimal, simply replace the percent sign with a decimal point and then move this decimal point two places to the left; after this, you can drop any trailing zeros. Here are a few common conversions between percents and decimals:

 100% = 1 75% = 0.75 50% = 0.5 25% = 0.25 20% = 0.2 10% = 0.1

Sometimes a percent already has a decimal point. In this case, just drop the percent sign and move the decimal point two places to the left. For instance, 12.5% = 0.125.

## Sample questions

1. Change 80% to a decimal.

0.8. Replace the percent sign with a decimal point — changing 80% to 80 — and then move the decimal point two places to the left:

80% = 0.80

At the end, you can drop the trailing zero to get 0.8.

2. Change 37.5% to a decimal.

0.375. Drop the percent sign and move the decimal point two places to the left:

37.5% = 0.375

## Practice questions

1. Change 90% to a decimal.

2. A common interest rate on an investment such as a bond is 4%. Convert 4% to a decimal.

3. Find the decimal equivalent of 99.44%.

4. What is 243.1% expressed as a decimal?

Following are answers to the practice questions:

1. 0.9. Replace the percent sign with a decimal point and then move this decimal point two places to the left:

90% = 0.90

At the end, drop the trailing zero to get 0.9.

2. 0.04. Replace the percent sign with a decimal point and then move this decimal point two places to the left:

4% = 0.04

3. 0.9944. Drop the percent sign and move the decimal point two places to the left:

99.44% = 0.9944

4. 2.431. Drop the percent sign and move the decimal point two places to the left:

243.1% = 2.431