The cartesian product of A x B = B x A

Explanation

The cartesian product will give a set of ordered pair where the first element belong to the first set in the cartesian product and the second element belongs to the second set in the cartesian product.  So, let A = {1, 2}, and B = {3, 4}

A x B = {(1, 3), (1, 4), (2, 3), (2, 4)}

B x A = {(3, 1), (3, 2), (4, 1), (4, 2)}

Order of element in ordered pair is material.  Thus

A x B ≠ B x A