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Multiplying Decimals
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.
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.
To Multiply:
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.
EXAMPLE 1 Multiplying Decimals
Multiplying Decimals
5.82
0.41
2 decimal places
2 decimal places
5 8 22 3 2 8
4 decimal places
–––+––––––
2.3 8 6 2–––––––
1234
6.45
18
2 decimal places
0 decimal places
5160645
––––––116.10
EXAMPLE 2 Multiplying Decimals
–––+––––––
After you place the decimal point, you can drop any zeros at the end of an answer.
2 decimal places
Multiplying Decimals
ANSWER 6.45 18 = 116.1
Write a zero before the 7 as a placeholder so that the number has 5 decimal places.
6.45
18
2 decimal places
0 decimal places
5160645
––––––116.10
1.273
0.06
3 decimal places
2 decimal places
76380.0 5 decimal places
EXAMPLE 3 Multiplying Decimals
–––+–––––– ––––––– –––+
After you place the decimal point, you can drop any zeros at the end of an answer.
2 decimal places
Multiplying Decimals
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 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)
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 12. 277 x 10 = 122.77
Ex) Multiply 132. 277 x 100 = 13227.7
Ex) Multiply 42. 587 x 10000 = 425870.0
