- Definition of Subtraction
- Subtraction of Signed Numbers

Summary: This module is from Elementary Algebra by Denny Burzynski and Wade Ellis, Jr. The basic operations with real numbers are presented in this chapter. The concept of absolute value is discussed both geometrically and symbolically. The geometric presentation offers a visual understanding of the meaning of |x|. The symbolic presentation includes a literal explanation of how to use the definition. Negative exponents are developed, using reciprocals and the rules of exponents the student has already learned. Scientific notation is also included, using unique and real-life examples. Objectives of this module: understand the definition of subtraction, be able to subtract signed numbers.

- Definition of Subtraction
- Subtraction of Signed Numbers

We know from our experience with arithmetic that the subtraction

We begin at 0, the origin.

Since 5 is positive, we move 5 units to the right.

Then, we move *2 units to the left* to get to 3. (This reminds us of addition with a negative number.)

This illustration suggests that

This leads us directly to the definition of subtraction.

If

The preceding definition suggests the rule for subtracting signed numbers.

To perform the subtraction

Perform the subtractions.

The high temperature today in Lake Tahoe was

We need to find the difference between 26 and

Thus, the expected temperature drop is

Perform the subtractions.

3

18

13

118

16

10

0

For the following exercises, perform the indicated operations.

5

5

11

5

7

29

164

1

1

8

4

6

When a particular machine is operating properly, its meter will read 34. If a broken bearing in the machine causes the meter reading to drop by 45 units, what is the meter reading?

The low temperature today in Denver was

*((Reference))* Use the distributive property to expand

*((Reference))* Simplify

*((Reference))* Simplify

11

*((Reference))* Find the sum.

*((Reference))* Find the sum.

Comments:"Reviewer's Comments: 'I recommend this book for courses in elementary algebra. The chapters are fairly clear and comprehensible, making them quite readable. The authors do a particularly nice job […]"