LINQ:
*LINQ
*Any
*Zip
*Intersect
*Min
*Cast
*All
*Sum
*Take
*Max
*Skip
*Last
*Join
var numbers1to10 = new[] {1,2,3,4,5,6,7,8,9,10};
var numbers5to15 = new[] {5,6,7,8,9,10,11,12,13,14,15};
var numbers5to10 = numbers1to10.Intersect(numbers5to15);
Console.WriteLine(string.Join(",", numbers5to10));
//5,6,7,8,9,10