【正文】
members in the set. Example: The set of even numbers between 2 and 10 is of size 5:{2,4,6,8,10}. The set of primes between 2 and 10 is of size 4:{2,3,5,7}. Remember: Each member of set A belongs to A or is in the set A. A set can not have repeating member:{1,3,1,2}is not a set. Rearranging