Multiplying Decimals

To Multiply:• You do not line up the factors by the decimal.• Instead, place the number with more digits on top.• Line up the other number underneath, at the right.• Multiply• Count the number of decimal places (from the

right) in each factor.• Use the total number of decimal places in your

two factors to place the decimal in your product.

Example: 5.63 x 3.7

5.633.7x

1

2

4

4

39098

1

16+13

1

8

1

0

1

2

two

one

three.

Example: 0.53 x 2.6182.618 has more digits (4) than 0.53 (3), so it goes on top.

2.6180.53x

4

2

58

1

700

4

90

3

13000000+457

1

831

Decimal Places

three

two

five.

Try This: 6.5 x 15.3

15.36.5x

5

1

6

2

708

1

1

3

9+54

1

99

one

one

two.

Multiplication PropertiesCommutative Property of Multiplication: Factors can be multiplied in any order.

Example: 12 x 5 = 5 x 12

Associative Property of Multiplication: Factors can be grouped in any way.

Example: (2 x 3) x 5 = 2 x (3 x 5)

Identity Property of Multiplication: The product of any number and one is that number.

Example: 18 x 1 = 18