Rounding to Nearest 10 and 100 — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. What is 847 rounded to the nearest hundred?
A) 800
B) 840
C) 850
D) 900
To round 847 to the nearest hundred, look at the tens digit. The tens digit is 4, and 4 is less than 5, so we round down and keep the hundreds at 8. The answer is 800.
2. A farmer has 68 apples and picks 45 more. About how many apples are there when rounded to the nearest ten?
A) 100
B) 110
C) 120
D) 130
First add the apples: 68 + 45 = 113. To round 113 to the nearest ten, look at the ones digit. The 3 is less than 5, so 113 rounds down to 110.
3. Which of these numbers does NOT round to 300 when rounded to the nearest hundred?
A) 289
B) 312
C) 350
D) 251
350 has a tens digit of 5, so it rounds up to 400, not 300. The other numbers — 251, 289, and 312 — all round to 300, so 350 is the one that does not.
4. Rounding 455 to the nearest ten gives you what number?
A) 450
B) 460
C) 500
D) 400
To round 455 to the nearest ten, look at the ones digit. The ones digit is 5, and 5 or more rounds up, so 455 rounds up to 460.
Part B: Fill in the Blank
Write the correct answer on each line.
1. 724 rounded to the nearest hundred is 700.
The tens digit in 724 is 2, which is less than 5, so we round down. The hundreds digit stays at 7, giving 700.
2. 63 + 88 is about 150 when each number is rounded to the nearest ten.
Round each number to the nearest ten before adding. 63 has ones digit 3, so it rounds down to 60. 88 has ones digit 8, so it rounds up to 90. Then 60 + 90 = 150.
3. 537 rounded to the nearest ten is 540.
Look at the ones digit of 537 — it is 7. Since 7 is 5 or greater, we round up, so the tens digit moves from 3 to 4 and 537 rounds to 540.
4. When rounding 950 to the nearest hundred, the answer is 1000.
The tens digit of 950 is 5, so we round up. Rounding the hundreds up from 9 carries over into the thousands, giving 1000.
5. 91 - 47 is about 40 when each number is rounded to the nearest ten.
Round each number to the nearest ten first. 91 has ones digit 1, so it rounds down to 90. 47 has ones digit 7, so it rounds up to 50. Then 90 - 50 = 40.