Definition: Arithmetic mean is the average of a group of numbers. It is one of the most commonly used measures of central tendency.

In simple words: Add all the numbers together and divide the total by how many numbers there are.

Formula:

Example:

Find the mean of 10, 20 and 30.

Step 1: Add all the values.

10 + 20 + 30 = 60

Step 2: Count the values.

There are 3 values.

Step 3: Divide the sum by the number of values.

Answer: 20

Remember for exams:

• Arithmetic mean means average.
• First, add all the values.
• Then, divide the sum by the total number of values.