The subsets in math are;

- Venn Diagram. The venn diagram are closed circles, name after logician Robert Venn, the used to represent relationships between sets.

- Proper Subsets. 
when you've used venn diagram to find the Proper subsets, B is a proper 
subset of A.If there exist an element in A does not belong to B.

- Universal Subsets.
The set that contains all elements being discussed.

PS: Venn diagram consists of two types; The UNION, And INTERSECTION :)

Thanks ! I hope it would help you :)