Basic Mathematics for College Students

1.3 Subtracting Whole Numbers 35

EXAMPLE (^9) Radio Stations In 2005, there were 773 oldies radio
stations in the United States. By 2007, there were 62 less. How many oldies radio
stations were there in 2007? (Source:The M Street Radio Directory)
Strategy We will carefully read the problem, looking for a key word or phrase.
WHY Key words and phrases indicate which arithmetic operations should be used
to solve the problem.
Solution
The key phrase 62 less indicates subtraction. We translate the words of the problem
to numbers and symbols.
is less

 773  62

Use vertical form to perform the subtraction

In 2007, there were 711 oldies radio stations in the United States.

7 7 3

 6 2

7 1 1

The number of oldies

radio stations in 2007

62.

the number of oldies

radio stations in 2005

The number of oldies

radio stations in 2007

Self Check 9

HEALTHY DIETSWhen Jared Fogle

began his reduced-calorie diet of

Subway sandwiches, he weighed

425 pounds. With dieting and

exercise, he eventually dropped

245 pounds. What was his weight

then?

Now TryProblem 95

Using Your CALCULATOR The Subtraction Key: High School Sports

In the 2007–08 school year, the number of boys who participated in high

school sports was 4,367,442 and the number of girls was 3,057,266. (Source:

National Federation of State High School Associations) We can use the

subtraction key on a calculator to determine how many more boys than

girls participated in high school sports that year.

4367442 3057266

On some calculator models, the key is pressed instead of for the

result to be displayed.

In the 2007–08 school year, 1,310,176 more boys than girls participated in

high school sports.

ENTER 

  1310176



Evaluate expressions involving addition and subtraction.

In arithmetic, numbers are combined with the operations of addition, subtraction,
multiplication, and division to create expressions.For example,

15 6, 873 99, 6,512 24, and 42  7

are expressions.
Expressions can contain more than one operation. That is the case for the
expression 27  16 5, which contains addition and subtraction. To evaluate(find the
value of) expressions written in horizontal form that involve addition and subtraction,
we perform the operations as they occur from left to right.

6

EXAMPLE (^10) Evaluate: 27  16  5
Strategy We will perform the subtraction first and add 5 to that result.
WHY The operations of addition and subtraction must be performed as they
occur from left to right.
Self Check 10
Evaluate:
Now TryProblems 47 and 51

75  29  8