Average is also known as the arithmetic mean. Average is defined as the sum of all the observations divided by the total number of observations. 
If $x_{1}$, $x_{2}$, $x_{3}$, $x_{4}$..., $x_{n}$ are the set of observations, then 

Average = $\frac{x_{1} + x_{2} + x_{3} + x_{4}...+ x_{n}}{n}$.

Where, n is the total number of observations.

Given below are the solved examples based on average.

Question 1: Find the average of 6, 5, 1, 4.
Solution:
Given observations: 6, 5, 1, 4

Average = $\frac{x_{1} + x_{2} + x_{3} + x_{4}}{n}$

Average = $\frac{6 + 5 + 1 + 4}{4}$

Average = $\frac{16}{4}$ = 4

Therefore, the average of 6, 5, 1, 4 is 4.

Question 2: Find the average of 10, 12, 21, 1, 6.
Solution:
Given observations: 10, 12, 21, 1, 6

Average = $\frac{x_{1} + x_{2} + x_{3} + x_{4} + x_{5}}{n}$

Average = $\frac{10 + 12 + 21 + 1 + 6}{5}$

Average = $\frac{50}{5}$ = 10

Therefore, the average of 10, 12, 21, 1, 6 is 10.