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

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

3. Step 1: 8.5 X2.5 4 2 5 1 7 0 0 2 1 2 5 next…..

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

5. Step 1: 8.5 X2.5 4 2 5 1 7 0 0 2 1 2 5 next…..

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

7. Step 1: 8.5 X2.5 4 2 5 1 7 0 0 2 1.2 5

8. Try These: 1. 4.8 2. 3.55 x 0.5 x.05

9. Answers: 1. 4.8 2. 3.55 x 0.5 x.05 = 2.40 = 0.1775

10. Properties of Multiplication

11. 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. 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. 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. 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