Page 313 - Basic College Mathematics with Early Integers

290 C HAPTE R 4 I DECIMALS

PRACTICE 2 Example 2 Add: 763.7651 + 22.001 + 43.89

Add.
Solution: First we line up the decimal points.
a. 34.567 + 129.43 + 2.8903
b. 11.21 + 46.013 + 362.526 1 1 1
763.7651
22.0010 Insert one 0.
+ 43.8900 Insert two 0s.
829.6561 Add.
Work Practice 2

Don’t forget that the decimal point in a whole number is positioned after the
last digit.

PRACTICE 3 Example 3 Add: 45 + 2.06
Add: 119 + 26.072
Solution: 45.00 Insert a decimal point and two 0s.
+ 2.06 Line up decimal points.
47.06 Add.
Work Practice 3

Concept Check What is wrong with the following calculation of the sum of
7.03, 2.008, 19.16, and 3.1415?
7.03
2.008
19.16
+ 3.1415
3.6042

PRACTICE 4 Example 4 Add: 3.62 + (-4.78)
Add: 8.1 + (-99.2)
Solution: Recall from Chapter 2 that to add two numbers with different signs,
we find the difference of the larger absolute value and the smaller absolute value.
The sign of the answer is the same as the sign of the number with the larger
absolute value.
4.78
-3.62
1.16 Subtract the absolute values.
Thus, 3.62 + (-4.78) = -1.16
Î
The sign of the number with the larger absolute
value; -4.78 has the larger absolute value.
Work Practice 4
Answers
2. a. 166.8873 b. 419.749
3. 145.072 4. -91.1 Copyright 2012 Pearson Education, Inc.
Objective Subtracting Decimals
Concept Check Answer
Subtracting decimals is similar to subtracting whole numbers. We line up digits and
The decimal places are not lined up
properly. subtract from right to left, borrowing when needed.