Click the mouse button or press the Click the mouse button or press the Space Bar to display the answers.Space Bar to display the answers.

Objective

Find the product of decimals and whole numbers

Vocabulary

Scientific notation

A way of expressing a number as the product of a number that is at least 1 but less than 10

and the power of 10

Example 1 Multiply Decimals

Example 2 Multiply Decimals

Example 3 Annex Zeros in the Product

Example 4 Annex Zeros in the Product

Example 5 Scientific Notation

1/5

Find 18.9 4

Write the problem vertically line up digits, not place value

Multiply 4 9 = 36

Put the one’s place value of 6 under the 4

Carry the ten’s place value of 3

3

Multiply 4 8 = 32

Add the carry of 3 to 32 = 35

Put the one’s place value of 5 under the 8

Carry the ten’s place value of 3

3

1/5

Find 18.9 4Multiply 4 1 = 4

3 Add the carry of 3 to 4 = 7

Put the one’s place value of 7 under the 1

Count the decimal places in 18.9

31

Count the decimal places in 4

0

Add the place values 1 + 0

1

Beginning on the right of the 6, place a decimal 1 place to the leftAnswer: 75.6

Answer: 100.8

1/5

Find 12.6 8

4

2/5

Find 0.56 7

Write the problem vertically line up digits, not place value

Multiply 7 6 = 42

Put the one’s place value of 2 under the 7

Carry the ten’s place value of 4

Multiply 7 5 = 35

Add the carry of 4 to 35 = 39

Put the one’s place value of 9 under the 5

Carry the ten’s place value of 3

3

4

2/5

Find 0.56 7Multiply 7 0 = 0

Add the carry of 3 to 0 = 3

Put the one’s place value of 3 under the 0

3

Count the decimal places in 0.56

2

Count the decimal places in 7

0

Add the place values 2 + 0Beginning on the right of the 2, place a decimal 2 places to the leftAnswer: 3.92

2

Answer: 3.32

2/5

Find 0.83 4

3/5

1Find 3 0.016

Write the problem vertically line up digits, not place value

Since 0.016 has more digits than 3, put it on top

Multiply 3 6 = 18Put the one’s place value of 8 under the 3Carry the ten’s place value of 1Multiply 3 1 = 3Add the carry of 1 to 3 = 4Put the one’s place value of 4 under the 1

3/5

1

Find 3 0.016

Multiply 3 0 = 0

Put the one’s place value of 0 under the 0 next to the 1

Multiply 3 0 = 0

Put the one’s place value of 0 under the 0

Count the decimal places in 0.016

3

Count the decimal places in 3

0

Add the place values 3 + 0

3

Beginning on the right of the 8, place a decimal 3 places to the left

Answer: 0.048

Answer: 0.092

3/5

Find 4 0.023

ALGEBRA Evaluate

4/5

Write the algebraic expression5g

Remember: 5g means 5 g

Replace g with 0.0091

Bring down the 5

5 (0.0091)

Write the problem vertically line up digits, not place value

Since 0.091 has more digits than 5, put it on top

0.0091x 5

ALGEBRA Evaluate

4/5

0.0091x 5

Multiply 5 1 = 5

Put the one’s place value of 5 under the 5

5Multiply 5 9 = 45Put the one’s place value of 5 under the 9Carry the ten’s place value of 4

4

5

ALGEBRA Evaluate

4/5

0.0091x 5

Multiply 5 0 = 0

5Multiply 5 0 = 0

Put the one’s place value of 4 under the 0 next to the 9

4

5

Add the carry of 4 to 0 = 4

Put the one’s place value of 0 under the 0

40

Multiply 5 0 = 0Put the one’s place value of 0 under the 0

0

ALGEBRA Evaluate

4/5

0.0091x 5

0 0455

4 Count the decimal places in 0.0914 Count the decimal places in 50

Add the place values 4 + 0

Beginning on the right of the 5, place a decimal 4 places to the left

.

Answer: 0.0455

4

ALGEBRA Evaluate

Answer: 0.0186

4/5

ASTRONOMY The average distance from Earth to the Sun is 1.5 108 kilometers. Write this distance in standard form.

5/5

Write the problem1.5 108 Use the calculatorPut 1.5 in calculator

1.5

Push the sign

Put 10 in calculator

10

Push the exponent key [yx]

yx

ASTRONOMY The average distance from Earth to the Sun is 1.5 108 kilometers. Write this distance in standard form.

5/5

1.5 108

1.5 10 yx

Put the exponent 8 in calculator

8 Push the = sign

=

150,000,000 Make sure to add the commas in the appropriate places

Answer: The average distance is 150,000,000 kilometers

Answer: 240,000 years

ARCHAEOLOGY An archaeologist claims that a particular artifact is 2.4 105 years old. Write this age in standard form.

*

5/5

Assignment Lesson 4:1 Multiplying Decimals 15 - 38 All

  by Whole Numbers