Unit 2

Factoring by 10

100

Complete the steps to find 30 x 40 by factoring the tens.

30 x 40 = ( 3 x 10) x (___ x 10)

            = (3 x __) x (10 x 10)

            = ____ x 100

            = _____

30 x 40 = ( 3 x 10) x (_4_ x 10)

            = (3 x _4_ ) x (10 x 10)

            = _12_ x 100

            = __1,200__

200

Complete the steps to find 20 x 70 by factoring the tens.

20 x 70 = ( ___ x 10) x (___ x 10)

            = (2 x 7) x (___ x ___)

            = ____ x 100

            = _____

20 x 70 = (_2_ x 10) x (_7_ x 10)

            = (2 x 7) x (_10_ x _10_)

            = _14_ x 100

            = __1,400__

300

80 x 90 = (___ x ___) x (9 x 10)

            = ( ___ x 9) x (10 x 10)

            = ____ x 100

            = ______

80 x 90 = (_8_ x _10_) x (9 x 10)

            = (_8_ x 9) x (10 x 10)

            = _72_ x 100

            = __7,200__

400

70 x 40 = (__ x 10) x (__ x __)

            = (__ x __) x (10 x 10)

            = __ x 100

            = ____

70 x 40 = (_7_ x 10) x (_4_ x _10_)

            = (_7_ x _4_) x (10 x 10)

            = _28_ x 100

            = _2,800_

500

70 x 80 = (__ x __) x (__ x __)

            = (__ x __) x (__x __)

            = ___ x ___

            = ____

70 x 80 = (_7_ x _10_) x (_8_ x _10_)

            = (_7_ x _8_) x (_10_x _10_)

            = _56_ x _100_

            = _5,600_

SURPISE

100

9 x 398

3,582

200

Estimate:

93 x 16

90 x 20

= 1,800

300

Multiply:

4,406 x 8

4,406 x 8

= 35,248

400

56 x 23

56 x 23

=1,288

500

13 x 80

13 x 80

= 1,040

Word Problems

100

Tickets to watch Mason's team play on the Detroit Lions football field was $57 per ticket. If someone buys 6 tickets, what will be the total cost?

57 x 6

= $342

200

Tegan went to the U of M sports store to buy foam fingers befor the U of M versus Michigan State game. He found that the foam fingers cost $9 each. If Tegan buys 184 foam fingers for everyone he is sitting next to at the game, how much will he pay altogether?

9 x 184 

= $1,656

300

Faith went and bought 6 ponies and 8 sheep from a farmer because she said they looked cute. If each sheep cost $392, how much did the sheep cost altogether?

Extra information: 6 ponies

8 x $392 = $3,136

400

Gabe bought 37 boxes of pokemon cards on Monday. He then bought 26 boxes of pokemon cards on Tuesday. Each box weighs 5 pounds. How many pounds do the boxes of pokemon cards weigh in all?

37 + 26 = 63 total boxes of pokemon cards

63 boxes x 5 pounds = 315 pounds

500

Kareena was selling 86 sweatshirts for $54 each. About how much money did Kareena make? (Estimate!!)

86 x 54  -->   Round first to estimate!   -->   90 x 50 

About $4,500

Solve!

100

13 x 9

13 x 9 = 

117

200

36 x 8

36 x 8 = 

288

300

1,768 x 3

1,768 x 3

= 5,304

400

43 x 28

43 x 28

= 1,204

500

87 x 94

87 x 94

= 8,178

Estimate and Solve!

100

3 x 12

3 x 10 

= 30

200

8 x 57

8 x 60

= 480

300

68 x 35

70 x 40

= 2,800

400

4 x 2,933

4 x 3,000

= 12,000

500

Choose the best estimate of the product.

8 x 2,319

a. (8 x 3,000) + (8 x 300) = 26,400

b. (8 x 2,000) + (8 x 400) = 19,200

c. (8 x 2,000) + (8 x 300) = 18,400

d. (8 x 3,000) + (8 x 400) = 27,200

8 x 2,319

c. (8 x 2,000) + (8 x 300) = 18,400