Two by Two
23 x 30
690
21 x 40
840
Which two expressions are equal to 420?
A - 42 x 10
B - 40 x 10 + 2
C - 40 x 10 + 20 x 10
D - 40 x 10 + 2 x 10
A and D
Mr. Luca bought 28 notebooks. Each notebook has 54 pages. What is a good way to estimate the total number of pages he has?
30 x 50 = 1,500
A box has 16 books packed inside. How many books would be in 40 boxes?
640 books
The product of two factors is 1,200. One of the factors is 20. What is the missing factor?
A - 40
B- 120
C- 60
D - 600
C - 60
15 x 16
240
Select all the expressions that are equal to 260.
A - 23 x 10
B - 20 x 10 + 3 x 10
C. 13 x 20
D. 10 x 20 + 3 x 20
C and D
Nika has a contract and needs to make 37 beaded necklaces. She puts 42 beads in each necklace. What is the estimated answer of beads used?
40 x 40 = 1,600 beads
A box has 16 books packed inside. How many books would be in 60 boxes?
960 books
14 x 12
168
49 x 21
1,029
Write 328 in expanded form
300 + 20 + 8
Graham swam 14 laps 12 times in May. He swam 15 laps 16 times in June. How many laps did Graham swim during the two months?
408 laps
The lawn service charges $85 to mow, weed, and fertilize a lawn. How much did the lawn service earn if 15 lawns were tended in June and 23 lawns in July?
$3,230
27 x 12
324
13 x 16
208
Write 1,098 in expanded form.
1,000 + 90 + 8
The lawn service charges $85 to mow, weed, and fertilize a lawn. About how much did the lawn service earn if 15 lawns were tended in June and 23 lawns in July?
(90 x 20) / (85 x 20) = 1,800 / 1,700
(90 x 20) / 85 x 20) = 1,800 / 1,700
(1,800 + 1,800) / (1,700 + 1,700) =
3,600 / 3,400
Spencer has a rock collection. He has 13 boxes filled with 16 rocks each. How many rocks does he have altogether?
208 rocks
18 x 10
180
Find exact and estimated answer.
12 x 37
Exact: 444
Estimated: 400
Write two expressions that would equal 280.
70 x 4
or
10 x 7 x 4
One mural is 27 ft by 12 ft. Another mural is 18 ft by 10 ft. What is the difference between the areas of the two murals?
144 square ft
A bakery has 12 bins of bagels. Each bin is filled with 37 bagels. Use properties of operations to find the total number of bagels. Use rounding to check your answer.
37 x 12 = 444
10 x 40 = 500
or
12 x 40 = 480