If $A = \{2, 3, 4\}$ and $B = \{1, 2\}$, then $n(A \times B) =$

The number of ordered pairs equals the product of the sizes of the two sets. With $n(A) = 3$ and $n(B) = 2$, we get $n(A \times B) = 3 \times 2 = 6$.