Complete guide to rounding decimals to one decimal place
The **tenth place** is the first digit after the decimal point. It's also called "one decimal place." When you round to the nearest tenth, you're keeping just one digit after the decimal.
3.456
The 4 is in the tenths place
This is the first digit after the decimal point.
Example: In 3.456, the tenths place is 4
The digit in the hundredths place (second decimal) tells you whether to round up or down.
Example: In 3.456, the hundredths digit is 5
If the hundredths digit is 5 or greater → round UP
If the hundredths digit is less than 5 → round DOWN
Example: Since 5 ≥ 5, round UP from 3.4 to 3.5
Keep only one decimal place.
Final Answer: 3.456 rounded to the nearest tenth = 3.5
Original number: 7.89
Tenths place: 8
Hundredths place: 9 (this is ≥ 5)
Decision: Round UP
Answer: 7.9
Original number: 12.34
Tenths place: 3
Hundredths place: 4 (this is < 5)
Decision: Round DOWN (keep the 3)
Answer: 12.3
Original number: 0.666
Tenths place: 6
Hundredths place: 6 (this is ≥ 5)
Decision: Round UP (6 becomes 7)
Answer: 0.7
| Original Number | Look At | Decision | Rounded to Tenth |
|---|---|---|---|
| 3.14159 | Hundredths: 4 | 4 < 5 → Down | 3.1 |
| 8.95 | Hundredths: 5 | 5 = 5 → Up | 9.0 |
| 5.678 | Hundredths: 7 | 7 ≥ 5 → Up | 5.7 |
| 2.02 | Hundredths: 2 | 2 < 5 → Down | 2.0 |
| 99.99 | Hundredths: 9 | 9 ≥ 5 → Up | 100.0 |
| 1.234 | Hundredths: 3 | 3 < 5 → Down | 1.2 |
Weather forecasts often use tenths:
GPAs use one decimal place:
Product ratings to one decimal:
Weight, height, distance:
If you start with a whole number, add .0 when rounding to tenths:
5 rounded to nearest tenth = 5.0
When the hundredths digit is exactly 5, always round UP:
2.15 → 2.2 (not 2.1)
3.45 → 3.5 (not 3.4)
You can drop or keep trailing zeros after rounding:
5.0 = 5 (both are correct)
12.0 = 12 (both are correct)
Look at the second decimal
5 or more? Round UP ⬆️
Less than 5? Round DOWN ⬇️
3.46 → 3.5 (6 ≥ 5)
7.23 → 7.2 (3 < 5)
9.95 → 10.0 (5 = 5)