If set A = {1, 2, 3} and set B = {2, 3, 5, 7}. Then the number of elements in A × B is
Number of element in A × B = number of element in A × number of element in B.
= 3 × 4 = 12
A × B = {(1, 2), (1, 3), (1, 5), (1, 7), (2, 2), (2, 3), (2, 5), (2, 7), (3, 2), (3, 3), (3, 5), (3, 7)}
No of element in A × B = 12