1. Chapter 1 / Whole Numbers and Introduction to Algebra
Graphs
Graphs are used to present numerical information in picture form. Two common forms of graphs are bar graphs and line graphs (otherwise known a broken-line graphs).

2. Chapter 1 / Whole Numbers and Introduction to Algebra
Bar Graphs
Bar graphs can appear with vertical bars or horizontal bars. An advantage to using bar graphs is that a scale is usually included for greater accuracy.

3. Chapter 1 / Whole Numbers and Introduction to Algebra
Bar Graphs
Source: United Nations, Dept. for Economic and Social Information and Policy Analysis
The bar graph shows the population of the world’s largest cities.

4. Chapter 1 / Whole Numbers and Introduction to Algebra
Histograms
A histogram is a special bar graph. The width of each bar represents a range of numbers called a class interval. The height of each bar corresponds to how many times a number in the class interval occurred and is called the class frequency. The bars in a histogram lie side by side with no space between them.

5. Chapter 1 / Whole Numbers and Introduction to Algebra
Histograms
40-49 1
50-59 3
60-69 2
70-79 10
80-89 12
90-99 8
Student Scores
Frequency (# of students)
The test scores of 36 students are summarized in the table.

6. Chapter 1 / Whole Numbers and Introduction to Algebra
Line Graphs
Chapter 1 / Whole Numbers and Introduction to Algebra
Another common way to display information graphically is by using a line graph. An advantage of a line graph is that it can be used to visualize relationships between two quantities. A line graph can also be very useful in showing change over time.

7. Line Graphs Tornado Deaths Average Number of U.S. Deaths (1966-1999)5 10 15 20 25 30
Jan.
Feb.
March
April
May
June
July
August
Sept.
Oct.
Nov.
Dec.
Source: Storm Prediction Center
Average Number of U.S. Deaths ( )

8. Chapter 1 / Whole Numbers and Introduction to Algebra
Circle Graphs
A circle graph is often used to show percents in different categories, with the whole circle representing 100%.

9. Source: Office of Travel and Tourism Industries
Circle Graphs
The following graph shows the percent of visitors to the United States in a recent year by various regions.
Source: Office of Travel and Tourism Industries

10. Examples
How much more money did Juan spend on meats, fruits, vegetables, breads, and dairy products than on entertainment and junk food?

11. Examples
The daily high temperatures recorded during the week were as follows: Monday, 86°F, Tuesday, 80°F, Wednesday, 75°F, Thursday, 82°F, Friday, 88°F, Saturday, 74°F, and Sunday, 84°F.
Make a bar graph and a
broken-line graph that
presents this information.

12. Examples
What is the average number of type B cars sold in the 3 years shown?