It is very simple to use and draw Venn diagrams. A Venn diagram is made up of two circles. These circles represent two different items and if one or some of their characteristics are the same then the circles will overlap, otherwise they will not. In the case above, number which are divisible by 3 which are: 3,6,12,24 will come in the first circle and numbers that are divisible by 5 will come in the other circle, whereas numbers that are divisible by both will come in the overlapping section, these numbers are 15 and 30.