In math terms, the "range" is the difference between the maximum and minimum values of a given data set. It is a calculation that measures the spread of a data set. However, range can also mean all the output values of a function.
The equation used to find the range of a data set is "maximum value - minimum value = range." To find the range of the data set given as "5, 7, 9, 1, 11, 4, 8, 5 and 12," one finds the minimum value of the data set as 1. The maximum value is 12. By subtracting these two values, the range is 11, or "12 - 1 = 11."
To find the maximum and minimum values of a data set that contains many values, order the values in the set from lowest to greatest.
MathisFun.com points out that the range of a data set can be misleading if there are outliers in the data. When the term range is being used to mean all the output values of a function, it is often called the range of a function to distinguish its meaning.