Basic Mathematics for College Students

The collection of positive whole numbers, the negatives of the whole numbers,
and 0 is called the set of integers(read as “in-ti-jers”).

2.1 An Introduction to the Integers 133

Positive and Negative Numbers

Positive numbersare greater than 0.Negative numbersare less than 0.

Caution! Zero is neither positive nor negative.

The three dots on the right indicate that the list continues forever—there is no
largest integer. The three dots on the left indicate that the list continues forever—
there is no smallest integer. The set of positive integersis and the set
of negative integersis .{... , 5, 4, 3, 2, 1}

{1, 2, 3, 4, 5,... }

The Set of Integers

{... , 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5,... }

The Language of Mathematics Since every whole number is an integer, we

say that the set of whole numbers is a subsetof the integers.

The set of integers {... , 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5,... }

2 Graph integers on a number line.

In Section 1.1, we introduced the number line. We can use an extension of the number
line to learn about negative numbers.
Negative numbers can be represented on a number line by extending the line to
the left and drawing an arrowhead. Beginning at the origin (the 0 point), we move to
the left, marking equally spaced points as shown below. As we move to the right on the
number line, the values of the numbers increase. As we move to the left, the values of
the numbers decrease.

Negative numbers Zero Positive numbers

Numbers get larger

Numbers get smaller

− 5 − 4 − 3 − 2 − 1012345

The thermometer shown on the next page is an example of a vertical number line.
It is scaled in degrees and shows a temperature of. The time line is an example
of a horizontal number line. It is scaled in units of 500 years.

10°

The set of whole numbers

e