Master rounding numbers to the nearest ten with simple rules
Rounding to the nearest 10 means finding which multiple of 10 (10, 20, 30, 40...) a number is closest to. The secret is simple: look at the ones digit!
If the ones digit is 5 or more (5, 6, 7, 8, 9):
Round UP to the next ten ⬆️
If the ones digit is less than 5 (0, 1, 2, 3, 4):
Round DOWN to the previous ten ⬇️
Find the rightmost digit (the ones place).
In 47, the ones digit is 7
Since 7 ≥ 5, round UP to the next ten.
47 is between 40 and 50, closer to 50
47 → 50
| Number | Ones Digit | Direction | Rounded to Nearest 10 |
|---|---|---|---|
| 23 | 3 (< 5) | Down ⬇️ | 20 |
| 27 | 7 (≥ 5) | Up ⬆️ | 30 |
| 45 | 5 (= 5) | Up ⬆️ | 50 |
| 82 | 2 (< 5) | Down ⬇️ | 80 |
| 96 | 6 (≥ 5) | Up ⬆️ | 100 |
| 134 | 4 (< 5) | Down ⬇️ | 130 |
| 178 | 8 (≥ 5) | Up ⬆️ | 180 |
| 995 | 5 (= 5) | Up ⬆️ | 1000 |
40
Previous ten
47
Ones digit is 7 (≥ 5)
50 ✓
Rounds to this!
Since 7 ≥ 5, we round UP to 50
"About how much will it cost?"
$47 → About $50
"About how many people came?"
134 people → About 130 people
Estimating distances or sizes
82 inches → About 80 inches
"It takes about how long?"
27 minutes → About 30 minutes
The ONES digit
(The rightmost digit)
5, 6, 7, 8, 9
0, 1, 2, 3, 4
5 is the magic number!
5 and above? Round up!