Percent means “per 100.” A percentage is a rate per 100.

We can use percentages to describe the relationship between two quantities. For instance:

• The value of a quarter is 25 percent of a dollar because there are 25 cents in a quarter per 100 cents in a dollar. The ratio of their values is 25 to 100.
• The value of a half-dollar coin is 50 percent of a dollar because there are 50 cents in a half-dollar coin per 100 cents in a dollar. The ratio of their values is 50 to 100.
• The value of five quarters is 125 percent of a dollar because there are 125 cents in five quarters per 100 cents in a dollar. The ratio of their values is 125 to 100.

Here is a double number line diagram that can represent these coin values. Because we’re representing percentages of a dollar, 100% is aligned to $1 on the number line.