Let's say 125 / 5
5 can't go into 1 so we move on to 12(if it doesn't work for twelve you move on to the next number). 5 goes into 12 twice because 5*2=10.
So the first number to our answer is 2 and we do 12-10=2. Then we bring down the 5 in 125 to make 25(from 12-10=2).
Since we are dividing by 5, 5 goes into 25 five times, so the next number to our answer is 5. 25-25=0 which means we can't divide by 5 any further so our answer is 25.
I think it's confusing but just for the points :)