Rounding to nearest 10 and 100

Rounding numbers to the nearest 10 and nearest 100

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Try each question. If you're stuck, leave it and come back. The answer key is on the last page.

1
Round 47 to the nearest 10. A) 40 B) 45 C) 50 D) 60
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2
Round 23 to the nearest 10. A) 10 B) 20 C) 25 D) 30
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3
Round 45 to the nearest 10. (Remember: 5 rounds up.) 45 rounded to the nearest 10 = ___
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4
Round 31 to the nearest 10. A) 20 B) 30 C) 31 D) 40
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5
Round 162 to the nearest 100. A) 100 B) 160 C) 170 D) 200
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6
Round 145 to the nearest 100. A) 100 B) 140 C) 150 D) 200
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7
Round 86 to the nearest 10. 86 rounded to the nearest 10 = ___
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8
Put these numbers in order from those that round DOWN to 100 to those that round UP to 200, smallest to largest. Put these in order: 120, 180, 110, 170
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9
Round 234 to the nearest 100. 234 rounded to the nearest 100 = ___
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10
Put these numbers in order of size, smallest to largest. They all round to 500 to the nearest 100. Put these in order: 478, 523, 451, 549
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Answer key

Rounding to nearest 10 and 100 · for parents and teachers

1
50
47 has a 7 in the ones, so we round up to 50.
2
20
23 has a 3 in the ones, so we round down to 20.
3
50
45 has a 5 in the ones, so it rounds up to 50.
4
30
31 has 1 in the ones place, so round down to 30.
5
200
162 has a 6 in the tens. 6 is 5 or more, so we round up to 200.
6
100
145 has a 4 in the tens, so we round down to 100.
7
90
86 has a 6 in the ones, so we round up to 90.
8
110, 120, 170, 180
In order: 110, 120, 170, 180. 110 and 120 round to 100; 170 and 180 round to 200.
9
200
234 has a 3 in the tens, so we round down to 200.
10
451, 478, 523, 549
451 < 478 < 523 < 549. All four numbers round to 500 to the nearest 100 because 451 and 478 round up, and 523 and 549 round down.