Estimating
#1 Don works 18 hours a week which expression shows a good way to use rounding to estimate how many hours Don will work in 52 weeks?
a. 10 x 50 b. 10 x 60 c. 20 x 50 d. 18 x 60
c. 20 x 50
#6 Margo hiked 12 miles 13 times last month. She hiked 14 miles 12 miles this month. Draw area models to find the number of miles Margo hiked during the past two months.
10 3 10 2
10 10x10 10x3. 10 10x10. 10x2
2 2 x 10 2x3. 4. 4x10. 4x2
100+30+20+6. 100+40+20+8
156. 168
156 +168=324
#26 What is the product
456
x 52
_____
23,712
#9 Check if Avery's work is reasonable. Correct the work if needed.
Missing place value holder.
Actual Answer : 3,956
#2 There are 26 bottles of paint in one set. How many bottles of paint are in 52 sets?
1,352
#7 A florist makes centerpieces. He puts 18 roses in each centerpiece. Which is the best way to use compatible numbers to estimate the number of roses the florist needs for 24 centerpieces? What is the exact number of roses?
b. 20 x 25 = 500 ; 432
# 22 Lorin drew an area model to find 19 x 15. Write the partial product for each rectangle in the area model.
10. 5
10. A. B
9. C. D.
A. 10 x 10 = 100
B. 10 x 5 = 50
C. 9 x 10 = 90
D. 9 x 5 = 45
# 27 A factory makes 132 laptops each day. How many laptops does the factory make in 45 days?
5,940 laptops
# 13 Find the product of 21 x 40. Show your work!
840
$24,192
# 18 Select all products with an estimate close to 150,000.
288 x 491 , 482 x 327, 313 x 507 , 368 x 642 ,
375 x 231
288 x 491 , 482 x 327, 313 x 507
# 25 Draw an area model to multiply 12 x 83
80. 3
10 10 x 80. 10 x 3
2. 2 x 80 2 x 3
800 + 160 + 30 + 6
= 996
# 16 One box has 27 jars of strawberry jam. How many jars are in 82 boxes?
2,214 jars
# 21 Use standard algorithm to find the product
86
x 68
______
5,848
#17 Which number makes the equation true?
40 x ____ = 16,000
400
# 23 Which is the best estimate for 176 x 742?
140,000
# 14 B. How many packages does Cargo Express deliver in a month?
2,730 packages
# 14 A. How many packages does Transport Truck deliver in a month?
4,800 packages
#14 C. How many packages does Trusty Wheels deliver in a month?
5,184 packages
#11 Jack's landscape service charges $78 to plant a tree. What is the total cost to plant 18 trees on Tuesday and 23 trees on Wednesday? Write and solve equations.
78 x 18 = 1,404
78 x 23 = 1,794
# 10 Manuela goes to school 180 days this year. Each day, she spends 425 minutes at school. About how many minutes does Manuela spend at school this year?
80,000 minutes
# 20 What is the product? 700 x 900
630,000
# 19 Antonio practices piano for 30 minutes each day. How many minutes does Antonio practice in 60 days?
1,800 minutes
1,242
# 12 Which of the following uses properties of operations to help find 27 x 14?
(20+7) x (10+4)