Question 8
If $A=\{p,i,m,s,o\}$ and $B=\{1,2,3,4,5,6,7,8,9\}$ then $D=A\times B=\{p,i,m,s,o\}\times\{1,2,3,4,5,6,7,8,9\}$. How many subsets does D have? Hint! $M=\{1,2\}$, $N=\{3,4,5\}$, $M\times N\;\{(1,3),(1,4),(1,5),(2,3),(2,4),(2,5)\}$. Subset: A set whose elements are all members of another set.