Given that p, q: $(1,2,3,4,5,6$, )
For $\frac{\mathrm{p}}{\mathrm{q}}$ form, when $\mathrm{p}=1, \mathrm{q}=1,2,3,4,5,6$
thus, $\frac{\mathrm{p}}{\mathrm{q}}=1, \frac{1}{2}, \frac{1}{3}, \frac{1}{4}, \frac{1}{5}$ and $\frac{1}{6}$
$\mathrm{n}=\left(\frac{\mathrm{p}}{\mathrm{q}}\right)=6$
When $p=2, q=1,3,5$
thus $\frac{\mathrm{p}}{\mathrm{q}}=2, \frac{2}{3}, \frac{2}{5}$ and $\mathrm{n}\left(\frac{\mathrm{p}}{\mathrm{q}}\right)=3$
When $\mathrm{p}=3, \mathrm{q}=1,2,4,5$
thus $\frac{\mathrm{p}}{\mathrm{q}}=3, \frac{3}{2}, \frac{3}{4}, \frac{3}{5}$ and $\mathrm{n}\left(\frac{\mathrm{p}}{\mathrm{q}}\right)=4$
When $\mathrm{p}=4, \mathrm{q}=1,3,5$
thus $\frac{\mathrm{p}}{\mathrm{q}}=4, \frac{4}{3}, \frac{4}{5}$ and $\mathrm{n}\left(\frac{\mathrm{p}}{\mathrm{q}}\right)=3$
When $p=5, q=1,2,3,4,6$
thus $\left(\frac{p}{q}\right)=5, \frac{5}{2}, \frac{5}{3}, \frac{5}{4}$ and $\frac{5}{6}$ and $\mathrm{n}\left(\frac{\mathrm{p}}{q}\right)=5$
When $\mathrm{P}=6, \mathrm{q}=1,5$
thus $\left(\frac{p}{q}\right)=6, \frac{6}{5}$ and $n\left(\frac{p}{q}\right)=2$
Hence, cardinality of the set (s) $=6+3+4+3+5+2=23 .$