**The mean is the average of a set of numbers.** It is the sum of all the items in a set, divided by the total number of items in the set.

A group of numbers can be referred to as a **set.**

**Example:** 15, 4, 37, 18, 11.

**Mean of two numbers:**

When there are only two numbers, the **mean** is easy to find. It is simply the number that is halfway between the two numbers of the set.

**Example:**

In this example, the set is: 10, 40.

Here, **25 is halfway between 10 and 40,** so it is the mean.

Another way to find the mean, or average, is to find the sum of the numbers and divide by 2:

**Mean of more than two numbers:**

Consider the set: 10, 16, 40.

Here, find the sum of the three numbers and divide by the total numbers in the set, which is three.

Thus, the mean or average, is 22.

**Mean in real life: **

**Example:** There is a family with three kids and their ages are: 1, 3, and 5. To find out the mean age of all of the kids in the family, we would, **add together** all of their ages:

1 + 3 + 5 = 9

and then we would **divide** that number by the total number of kids.

9 ÷ 3 = 3

The kids in this family have a mean age of 3.