The arithmetic mean of a set of numbers (or variables) is the sum of all the numbers, divided by the number of numbers. If we let denote Arithmetic Mean,
is the arithmetic mean of the numbers .
For example, if I wanted to find the average of the numbers 3, 1, 4, 1, and 5, I would compute:
Arithmetic means are also called averages. Arithmetic means show up frequently in contest problems.