Adding and Subtracting Decimals

To add or subtract decimals, line them up so their decimal points are even. You may want to tack on zeroes at the end of shorter decimals so you can keep all your digits lined up evenly.

Remember, if a number doesn't have a decimal point, then put one at the right end of the number.

Problem: 1.23 + 57 + .038

1. Line up the numbers like this:

2. Add:

1.230

57.000+ .038 58.268

1.23 - .038

2. Subtract:

1.230- .038 1.192

Practice: Try these decimal addition and subtraction problems:

1. .905 + .02 + 3.075

2. .005 + 8 + .3

3. 3.48 - 2.573

4. 123.456 - 122

5. Officer Peterson drove 3.7 miles to the state park. He then walked 1.6 miles around the park to make sure everything was all right. He got back into the car, drove 2.75 miles to check on a broken traffic light and then drove 2 miles back to the police station. How many miles did he drive in total?

6. The average number of emergency room visits at City Hospital fell from 486.4 per week to 402.5 per week. By how many emergency room visits per week did the average fall? a. 73.9 b. 83 c. 83.1 d. 83.9 e. 84.9