Concepts
1 BasicFunctions
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Unit 1C
Review of Operations with
Decimal Fractions and Percent
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1.12
Multiplication and Division
of Decimal Fractions
Copyright © Cengage Learning. All rights reserved.
Multiplication and Division of Decimal Fractions
Multiplying Two Decimal Fractions
To multiply two decimal fractions:
1. Multiply the numbers as you would whole numbers.
2. Count the total number of digits to the right of the
decimal points in the two numbers being multiplied.
Then place the decimal in the product so that it has that
same total number of digits to the right of the decimal
point.
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Example 1
Multiply: 42.6  1.73.
Note that 42.6 has one digit to the right of
the decimal point and 1.73 has two
digits to the right of the decimal point. The
product has three digits to the right
of the decimal point.
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Multiplication and Division of Decimal Fractions
Dividing Two Decimal Fractions
To divide two decimal fractions:
Step 1: Use the same form as in dividing two whole
numbers.
Step 2: Multiply both the dividend and the divisor
(numerator and denominator) by a power of ten
that makes the divisor a whole number.
Step 3: Divide as you would with whole numbers, and
place the decimal point in the quotient directly
above the decimal point in the dividend.
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Example 3
Divide 24.32 by 6.4.
Method 1:
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Example 3
cont'd
Method 2:
Moving the decimal point one
place to the right in both the
dividend and divisor here is the
same as multiplying numerator
and denominator by 10 in
Method 1.
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Using a Calculator to Multiply and Divide
Decimal Fractions
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Example 7
Multiply: 8.23 x 65 x 0.4.
8.23
65
.4
The product is 213.98.
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