| Places | Tens | Ones | Tenths | Hundredths | |
|---|---|---|---|---|---|
| 1 | 1 | 1 | |||
| Number | 3 | 9 | . | 9 | 9 |
| Rounded Number | 4 | 0 | . | 0 |
- 9 is in the tenths place and 9 is in the hundredths place
- Since the digit in the hundredths place (9) is greater than or equal to 5, add 1 to the digit in the tenths place (9)
- 1 + 9 = 10, so the digit in the tenths place becomes 0, and 1 is added to the digit in the ones place (9)
- 1 + 9 = 10, so the digit in the ones place becomes 0, and 1 is added to the digit in the tens place (3)
- 1 + 3 = 4, so the digit in the tens place becomes 4
- The digits to the right of the tenths place are dropped
- 39.99 rounded to the nearest tenth (one decimal place) = 40.0
