The square of a number is that number multiplied by itself

Finding the square root of a number is the opposite action to squaring a number
We start with the squared number and work out what it's root is

For example if you wanted to place an advert on the side of a formula 1 car,
and you are told you are allowed an area on the car of 100cm²

Before you give them your advert you need to find the length of
one of the sides of the square area so your design will fit into the space

On your calculator you will have a square root button
put your squared number into your calculator
and push the square root button
100

The answer will give you the square root of your number
and the length your advert needs to be to fit onto the car!