# Average

An average or mean is a number that is typical of a group of numbers. The average of a group of numbers is often located in between, in the middle of that group of numbers. An average is found from the group of numbers by arithmetic.[1]

## To find an average

To find the average of $N$ numbers, the $N$ numbers are added and the total is divided by $N$.

In symbols, if the numbers are $X_1$, $X_2$, $X_3$, ... $X_N$, the total is:

$X_1 + X_2 + X_3 + ... + X_N$

The total is divided by $N$ to make the average:

${X_1 + X_2 + X_3 + ... + X_N} \over N$

### Examples

• Lucy is 5 years old. Tom is 6 years old. Emily is 7 years old. To find the average age:
• Add the three numbers :
$5+6+7=18$
• The total is 18. Divide the total 18 by three:
$18/3=6$
• The average of the three numbers is 6.
$\frac{5+6+7}{3}$
Therefore, the average age of Lucy, Tom and Emily is 6 years.

## Sport

In some sports, such as cricket and baseball, averages are used to tell how good a player is (such as batting average or bowling average). Sporting averages have special rules for how to calculate them.