Answer : Given: A = {2, 3} and B = {4, 5} To find: A × B

By the definition of the Cartesian product,

Given two non – empty sets P and Q. The Cartesian product P × Q is the set of all ordered pairs of elements from P and Q, .i.e.

P × Q = {(p, q) : p Є P, q Є Q}

Here, A = {2, 3} and B = {4, 5}. So,

A × B = (2, 3) × (4, 5)

= {(2, 4), (2, 5), (3, 4), (3, 5)}

∴Number of elements of A× B = n = 4 Number of subsets of A × B = 2n

= 24

= 2 × 2 × 2 × 2

= 16

∴, the set A × B has 16 subsets.