1. Multiplying Decimals
Lesson 1-7

2. 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.

3. Example: 5.63 x 3.7 1 4 2
5.63
two x
3.7
one 1 1 39 4 1 1 + 16 8 9 2 . 8 3 1
three

4. Example: 0.53 x 2.618
2.618 has more digits (4) than 0.53 (3), so it goes on top. 3 4
Decimal Places 1 2
2.618
three x
0.53
two 1 7 8 5 4 13 9 + 00 . 1 3 8 7 5 4
five

5. Try This: 6.5 x 15.3 3 1 2 1
15.3
one x
6.5
one 1 7 6 5 + 9 1 8 . 9 9 4 5
two

6. Multiplication Properties
Commutative 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