form subset from the set of a big circle with 20 stars inside in it.
A subset B of a given set A is a set in which all members of B are contained in A. If one member or more in A does not belong to B, the B is a proper subset of A.
Example:
A={cups, glasses, plates}
B={cups}
C={glasses, forks}
then B is a subset of A, and C is NOT a subset of A.