Estimation and Rounding — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Grade 4: 2,547 rounded to the nearest 1,000 is 3000.
The hundreds digit is 5, so 2,547 rounds up to 3,000.
2. Grade 4: 4,328 rounded to the nearest 1,000 equals 4000.
Since 3 is less than 5, 4,328 rounds down to 4,000.
3. In Grade 4, 7,892 rounded to the nearest 1,000 is 8000.
Because 8 is 5 or more, 7,892 rounds up to 8,000.
4. Grade 4: 1,499 rounded to the nearest 1,000 is 1000.
Since 4 is less than 5, 1,499 rounds down to 1,000.
5. Grade 4 estimate: 78 + 23 rounds to about 100 using nearest tens.
Estimating with rounded tens, 80 + 20 = 100, so the sum is about 100.
6. Grade 4 estimate: 412 + 289 is about 700 using nearest hundreds.
Rounded to hundreds, 400 + 300 = 700, a reasonable estimate.
7. Grade 4: 5,500 rounded to the nearest 1,000 is 6000.
The 5-or-more rule rounds 5,500 up to 6,000.
8. Grade 4 estimate: 63 + 38 is about 100 using nearest tens.
Rounded to tens, 60 + 40 = 100, a reasonable estimate of the sum.
9. In Grade 4, 9,250 rounded to the nearest 1,000 is 9000.
Because 2 is less than 5, 9,250 rounds down to 9,000.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Grade 4: 3,612 rounded to nearest 1,000
→ 4000
4000
Grade 4: 6,489 rounded to nearest 1,000
→ 6000
6000
Grade 4 estimate: 47 + 52 to nearest 10
→ 100
100
Grade 4 estimate: 198 + 305 to nearest 100
→ 500
500
3,612 rounds to 4,000; 6,489 rounds to 6,000; 47 + 52 rounds to 50 + 50 = 100; 198 + 305 rounds to 200 + 300 = 500.