Definition of



The Arithmetic Mean is the average of the numbers: a calculated "central" value of a set of numbers.

To calculate it:
• add up all the numbers,
• then divide by how many numbers there are.

Example: what is the mean of 2, 7 and 9?
Add the numbers: 2 + 7 + 9 = 18
Divide by how many numbers (i.e. we added 3 numbers): 18 ÷ 3 = 6
So the mean is 6

Note: there are other types of mean such as Geometric Mean and Harmonic Mean.