If set A has p elements and set B has q elements, number of elements in set (A × B) is _____.
If set A has p elements and set B has q elements, then the number of elements in set (A × B) is _____.
If set P = {2, 4, 6, 8} and set Q = {2, 3, 5, 7}. Find the number of elements in P × Q.