Copyright © Cengage Learning. All rights reserved. Functions 1 Basic Concepts

Copyright © Cengage Learning. All rights reserved. Unit 1C Review of Operations with Decimal Fractions and Percent

Copyright © Cengage Learning. All rights reserved. Multiplication and Division of Decimal Fractions 1.12

44 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.

55 Example 1 Multiply: 42.6  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.

66 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.

77 Example 3 Divide by 6.4. Method 1:

88 Example 3 Method 2: cont'd 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.

99 Using a Calculator to Multiply and Divide Decimal Fractions

10 Example 7 Multiply: 8.23 x 65 x The product is