Answer :

The mean is the average of the numbers. It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count.

AL2006
To find the average of a bunch of items (2 or more): . . . Add up all the items. . . . Divide the sum by the number of items. . . . The quotient of the division is their average.