One number that represents a group of numbers is called a/an

Average.

Explanation:

One number that represents a group of numbers is called an average. The most commonly used average in the real world for the calculation of different parameters such as gross pay, average pay, price, quantity etc, is the simple average.

In order to calculate an average, the total number of items are added together and then divided by the number of items.

For example, find the average of the salaries of five (5) employees who earn $10, $5, $50, $20 and $15 respectively.

Given, number of employees = 5

Total sum of money earned = 10+5+50+20+15 = 100

Average = Total sum of money/number of employees

Substituting the values, we have;

Average = 100/5

Average = 20.

Hence, the average pay of the five (5) employees is $20. This $20 represents a group of salaries earned by the five employees.