How do you rearrange equations at Physics GCSE ?

Take the equation W=Fs. We want to make one thing the subject of the equation by clearing away all the stuff we don’t want on that side of the equation. Say we want to find s. To do this draw a line under the equation like so: W=Fs. This helps us to remember how to move things from one side of the equation to the other. The rule when moving a value to the other side of the equation to leave one value by itself is: if the value you want to move is on top of the line then it moves to below the line, and if it is below the line, then it moves to above the line. With W=Fs , we want to leave s by itself. The F moves to the other side and because it is above the line on the right, it must go beneath the line on the left, under W.
W=Fs =>W/F=s 
By knowing the values of W and F, we can now work out s by dividing W by F.