交集和并集
Intersection of two sets is another set with only the members that are in both sets. If the two sets do not share any common member， the intersection is the empty set with no member.
Example：
Intersection of {1，2，3} and {2，3，5} is the set {2，3}。
Intersection of the set with all primes and the set with all even numbers is the set {2} since only 2 is both even and prime.
Intersection of {1，2，3} and {4，5，6} is the empty set {}。
Remember：
Intersection contains only the common members.
Two sets are disjoint if they have no member in common， that is they have an empty intersection.
union of Sets
union of two sets is another set with all the members from both sets.
以上是新GRE数学备考中关于交集和并集的内容，大家在备考的时候不妨分考点来复习，将做错的题整理出来，考前一个星期内集中再过一遍。
新GRE数学考点：Set
A set is a collection of objects or things. Each object in a set a member or element of that set.Size of a set is the number of 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 the order of the members does not change the set:{1,2,3}is same as{3,2,1}.
有一部分考生认为新GRE数学具有一定的难度，这其中的原因是由于考生在复习时没有把新gre数学的基础打牢。想要新gre数学考好，复习的时候一定要把基本概念和重要GRE数学考点都弄扎实。
最后，小编祝您考试顺利!