Is the element the number of numbers in a set?

2 answers

no, it is a member of the set
the order is the number of elements
For example, the sets:
A={2,4,6,8} B= {6,7,8,9,10}
when a question asks for the elements in B and the answer is n (B)=3 (that is the answer that my professor gave me) can I think of it as the numbers that are only found in set B? (7,9,10)
In set A and set B, the numbers 6 and 8 are both present.