Division is essentially a way of splitting something into equal parts and the value of one of those parts so i.e. 1 pizza divided by 2 would give you a resultant of 0.5 or half of 1 whole.
This is a very basic analogy using the decimal resultant value of one piece but there are 2 main methods of division, Short (Basic) and Long Division
Below are videos showing how this works.
Basic Division
Long Division when dividing by a number less than 10
Long Division when dividing with a number 10 or greater.