Estimation Strategies — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Lily computed 487 × 21 and got 1,022. Is this reasonable?
A) No, it should be near 10,000
B) Yes, it is correct
C) No, it should be near 100
D) Yes, near 1,000
500 times 20 equals 10,000, so 1,022 is far too small; the answer is unreasonable.
2. Which estimate is BEST for 7.85 × 3.9?
A) 20
B) 32
C) 45
D) 60
Eight times four equals 32, the closest reasonable estimate of the decimal product.
3. A baker has 4,872 cookies in 6 boxes. About how many per box?
A) 50
B) 500
C) 800
D) 8,000
4,800 divided by 6 equals 800, so each box holds about 800 cookies estimated.
4. Which sum is closest to 5,283 + 1,917?
A) 3,000
B) 5,000
C) 6,000
D) 7,000
Five thousand plus two thousand equals 7,000, the closest estimate among the choices.
Part B: Fill in the Blank
Write the correct answer on each line.
1. Estimate 612 × 78 by rounding to nearest 10: 48,000.
Six hundred ten times eighty equals 48,800, so the estimate is about 48,000.
2. Estimate 7,234 ÷ 9 using compatibles: 800.
7,200 divided by 9 equals 800, so 7,234 divided by 9 is about 800.
3. Estimate 3.87 × 5.2 to nearest whole: 20.
Four times five equals 20, the closest whole-number estimated product here.
4. Estimate 12,438 + 7,612 to nearest 1000: 20,000.
Twelve thousand plus eight thousand equals 20,000, a strong estimated sum.
5. Estimate $48.75 × 9 to nearest dollar: $450.
Fifty dollars times nine equals $450, an accurate estimated total cost.