Question

fast focus standard 3a / page 5
1 a chemist poured formaldehyde into three beakers. she poured 7.2 milliliters into the first, 8.97 milliliters into the second, and 3.12 milliliters into the third. the value of which expression is closest to the total number of milliliters of formaldehyde the chemist poured into the beakers?
a 7 + 9 + 3 c 7 + 10 + 3
b 7 + 8 + 3 d 7 + 10 + 4

2 mr. croce worked a total of 298 hours after 6 weeks. if he worked an equal number of hours each week, which is the best estimate of the number of hours he worked each week?
f 30 g 60 h 40 j 50

3 there are 28 days in the month of february and 31 days in the month of march. every day in february and march, lanelle will ride her bike 8.25 miles. which number sentence shows the estimated number of miles that lanelle will ride her bike in february and march?
a (20 + 30) × 8 = 400
b (30 + 30) × 8 = 480
c (20 + 30) × 9 = 450
d (30 + 30) × 9 = 540

4 simeon drew and labeled the rectangle shown below.
rectangle with length 6.87 cm and width 1.9 cm
which is the best estimate of the perimeter of the rectangle in centimeters?
f 19 g 18 h 21 j 16

fast focus standard 3a / page 6
1 martino has a block of ice that weighs 121.15 pounds. he will break the ice into small pieces and then divide the ice equally among 3 plastic sacks. which is the best estimate of the amount of ice he will place in each sack?
a 50 pounds c 60 pounds
b 40 pounds d 30 pounds

2 brody sprinkled 6.9 grams of pepper and 13.25 grams of salt on some roasted almonds. about how many more grams of salt did he sprinkle on the almonds than grams of pepper?
f 6.0 g 5.0 h 7.0 j 8.0

3 ms. torres will drive her car 392 miles on monday, 219 miles on tuesday, 318 miles on wednesday, and 362 miles on thursday. the value of which expression is closest to the total number of miles she will drive during the four days?
a 390 + 200 + 320 + 400
b 400 + 200 + 300 + 400
c 390 + 220 + 320 + 360
d 400 + 210 + 310 + 400

4 the heaviest delivery truck at trans-del trucking company weighs 36,732 pounds. the lightest truck weighs 22,394 pounds. which is the best estimate of the difference between the weights of the two trucks?
f 17,000 pounds h 15,000 pounds
g 13,000 pounds j 19,000 pounds

5 about how many months are in 18 years?
a 200 b 500 c 100 d 300

Explanation:

Page 5 Question 1

Step1: Round each value

7.2 ≈ 7, 8.97 ≈ 9, 3.12 ≈ 3.

Step2: Find the sum of rounded values

The sum is 7 + 9 + 3.

Step1: Estimate 298 hours

298 ≈ 300.

Step2: Divide by 6 weeks

300 ÷ 6 = 50? Wait, no, 298 is close to 300, but 300 ÷ 6 = 50? Wait, no, 298 ÷ 6 ≈ 50? Wait, 6×50=300, which is close to 298. Wait, but the options are F 30, G 60, H 40, J 50. So 298 ÷ 6 ≈ 50 (since 6×50=300, which is 2 more than 298). So the best estimate is 50? Wait, no, 298 is 2 less than 300, so 298 ÷ 6 ≈ 49.67, which is close to 50. So J 50.

Step1: Round the number of days

February has 28 days ≈ 30, March has 31 days ≈ 30. So total days ≈ 30 + 30 = 60.

Step2: Round the miles per day

8.25 miles ≈ 8.

Step3: Calculate total miles

Total miles ≈ (30 + 30) × 8 = 480. So option B.

Answer:

A

Page 5 Question 2