Decimal Multiplication

Estimating

100

6.23 x 11.7

6 x 11 = 66

or 6 x 10 = 60

200

187 x 3.15

200 x 3 = 600

190 * 3 = 570

300

Use estimation to place the decimal point in the correct location.

3.45 x 21.75 = 750375

75.0375

400

Use estimation to place the decimal point in the correct location.

0.73 x 5.2 = 3796

3.796

Multiplying by Powers of 10

100

Solve using the shortcut for multiplying by powers of ten:

2.31 x 10 

23.1

200

Solve using the shortcut for multiplying by powers of ten:

0.05 x 1,000 

50

300

Solve using the shortcut for multiplying by powers of ten:

  6.74 x 10²

674

400

5.9 x 0.1

0.59

500

6.72 x 0.01

0.0672

Whole number x Decimal

100

43 x 3.6 

154.8

200

0.21 x 9

1.89

300

13 x 3.73

48.49

Decimal x Decimal

100

0.02 x 0.44

0.0088

200

8.7 x 0.9

7.83

300

0.0501 x 0.31

0.015531

400

1.324 x 1.03

1.36372

Application Problems

100

Shannon exercises for 0.75 hour on Monday, Wednesday, and Friday each week.  How many hours will she exercise in 4 weeks?

9.0

200

A recipe calls for 1.75 cups of sugar to make a cake.  How many cups of sugar are needed for 4 cakes?

7.0

300

Parker needs 2.4 yards of ribbon.  Each yard of ribbon costs $0.90.  Shade the grid to model the product.  How much will the ribbon cost?  How does the model help you find the product? 

2.16