(2)Set builder notion: We characterize the property or properties that the elements of the set have in common. Example: The set A of odd positive integers less than 10 can be expressed by A=xx is an odd positive integer less than 10 Example: C=xx=y yEZ+) C describes the set of all cubes of positive integers D={x-1<x<2}( 2 ) Set builder notion: We characterize the property or properties that the elements of the set have in common. Example:The set A of odd positive integers less than 10 can be expressed by A={x|x is an odd positive integer less than 10} Example:C={x|x=y3 ,yZ+ } C describes the set of all cubes of positive integers. D={x|-1<x<2}