Exercise
Let M1 and M2 be finite semi-groups of order m1 and m2, respectively (order=number of elements). Then the order of the direct product is
m1 m2
m1 + m2
m1m2
Of course, this is just the size of the Cartesian product.
No, but accidentally correct if m1 = m2 = 2.
No, but accidentally correct if m1 = m2 = 2.