1. Multiplying Decimals & Properties of Multiplication
Christine Berg
Edited By V T Hamilton

2. Multiply as if the factors were whole numbers
Step 1:
Multiply as if the factors were whole numbers

3. Step 1:
8.5
X2.5
4 2 5
next…..

4. Count the total decimals places in the factors
Step 2:
Count the total decimals places in the factors

5. Step 1:
8.5
X2.5
4 2 5
next…..

6. Give the product the total decimal places of the factors
Step 3:
Give the product the total decimal places of the factors

7. Step 1:
8.5
X2.5
4 2 5

8. Try These:
x x

9. Answers:
x x
= =

10. Properties of Multiplication

11. The product of 1 and a number (a) is the number (a)
Identity Property
The product of 1 and a number (a) is the number (a)
1(a) = a

12. Examples
1 (b) = b
1 x 42 = 42

13. The product of 0 and a number (a) is 0
Zero Property
The product of 0 and a number (a) is 0
0 (a) = 0

14. Examples
0 (b) = 0
0 x 67 = 0

15. Changing the order of the factors does not change the answer
Commutative Property
Changing the order of the factors does not change the answer

16. Examples
a ( b ) = b ( a )
5 x 2 = 2 x 5

17. Changing the grouping of factors does not change the answer
Associative Property
Changing the grouping of factors does not change the answer

18. Examples
( a b ) c = a ( b c )
( 3 x 2 ) x 4 = 3 x ( 2 x 4 )

19. Try These:
Identify the property
( x y ) z = x ( y z )
0 x 4 = 0

20. Answers: ( x y ) z = x ( y z ) Associative Property of x 0 x 4 = 0
Zero Property