How to find out common element(s) in two generic list by LINQ, LINQ Set Operations

int[] twos = { 2, 4, 6, 8, 10 };

int[] threes = { 3, 6, 9, 12, 15 };

// 6

var intersection = twos.Intersect(threes);

// 2, 4, 8, 10

var except = twos.Except(threes);

// 2, 4, 7, 8, 10, 3, 9, 12, 15

var union = twos.Union(threes);