Original: Note how a (finite) multiset can also be considered as an unordered tuple: The tuples (a, b) and (b, a) are not equal because in tuples order is important.
Simplified: A multiset can also be considered an unordered tuple: The tuples (a,b) and (b,a) are not equal, and the tuples (a,a) and (a) are not equal either.