Median and average can be illustrated by an example.
Suppose please that five people work at a shop.
Two work on the counter, one also works on the counter but also orders some of the stock, one deputises for the manager when the manager is away, one is the manager.
Put their salaries in order from low to high.
£16000, £16000, £18000, £24000, £40000
The average salary is found by adding them up and dividing by how many there are.
So that is £114000 in total and there are 5 of them, so divide the £114000 by 5, giving £22800 as the average salary.
The median salary is the salary that has an equal number of salaries lower and above it.
So as there are 5 salaries, the median salary is the one that has 2 salaries below it and 2 salaries above it.
So for that example, the median salary is £18000.