Question

Let A = {1, 2} and let B = {3, 4, 5}. Find A X B

Answer 1

If we're talking sets, the cross of A and B is the set of tuples (x, y) such that x belongs to A and y belongs to B.
In this example: AxB={(1,3), (1,4), (1,5), (2,3), (2,4), (2,5)}