1. Multiplying Decimals

2. 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

3. 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.

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. 1 Multiplying Decimals  Multiplying Decimals 5.82 0.41 –––––– –––
EXAMPLE 1
Multiplying Decimals
5.82
2 decimal places
0.41
–––––– 
––– +
2 decimal places
5 8 2
–––––––
4 decimal places 4 1 3 2

6. 2 Multiplying Decimals  Multiplying Decimals 6.45 –––––– 18 ––– 5160
EXAMPLE 2
Multiplying Decimals
6.45
2 decimal places
––––––  18
0 decimal places
––– +
5160
645
––––––
116.10
2 decimal places
After you place the decimal point, you can drop any zeros at the end of an answer.
ANSWER
6.45  18 = 116.1

7. 3 Multiplying Decimals   Multiplying Decimals 6.45 1.273 18 ––––––
EXAMPLE 3
Multiplying Decimals
6.45
2 decimal places
1.273
3 decimal places 18
–––––– 
0 decimal places
––– +
––––––– 
0.06
––– +
2 decimal places
5160
0.0
7638
5 decimal places
645
––––––
116.10
2 decimal places
Write a zero before the 7 as a placeholder so that the number has 5 decimal places.
After you place the decimal point, you can drop any zeros at the end of an answer.

8. 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

9. 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)

10. If a Decimal number is multiplied by 10,100, 1000 etc
If a Decimal number is multiplied by 10,100, 1000 etc., the decimal shifts to the right side according to the number of Zeroes.
Ex) Multiply x 10 =
122.77
Ex) Multiply x 100 =
Ex) Multiply x =