Estimation Strategies — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A store sells 213 phone cases at $8.95 each. About how much money does the store earn?
A) About $1800
B) About $180
C) About $18000
D) About $200
200 times $9 equals $1,800, the most reasonable order-of-magnitude estimate here.
2. A jogger covers 3.85 km in 0.5 hour. About what is the speed in km per hour?
A) About 2
B) About 8
C) About 20
D) About 40
4 km divided by 0.5 hour equals 8 km per hour, the closest reasonable estimate.
3. A field is 78 m by 24 m. About what is the area of the field in square meters?
A) About 200
B) About 800
C) About 2000
D) About 20000
80 meters times 20 meters equals 1,600, closest to about 2,000 square meters.
4. A jar holds 1,950 mL. About how many 9.8 mL doses fit in the jar approximately?
A) About 20
B) About 100
C) About 50
D) About 200
2,000 divided by 10 equals 200, the right order-of-magnitude estimate here.
Part B: Fill in the Blank
Write the correct answer on each line.
1. A farmer sells 412 bags of apples at $4.85 each. Estimated income is about $2000.
400 times $5 equals $2,000, a fast and close income estimate.
2. A pool holds 2,895 gallons. Filling at 28.5 gal per minute takes about 100 minutes.
3,000 divided by 30 equals 100 minutes, a clean compatible-number time estimate.
3. A pizza shop uses 0.18 lb of cheese per pizza for 52 pizzas. About 10 lb total.
0.2 lb times 50 pizzas equals 10 lb, a quick reasonable cheese estimate.
4. A bus travels 287 km on 9.8 L of fuel. Estimated kilometers per liter is about 30.
300 km divided by 10 L equals 30 km per liter, a clean fuel estimate.
5. Tickets cost $24.85 each for 39 friends. Estimated total cost is about $1000.
$25 times 40 equals $1,000, a quick and close estimate of total cost.