$\frac{8m}{n}:\frac{4m}{n}=\frac{8m}{n}\ast <!--\; \ast \; -->\frac{n}{4m}=\frac{2}{1}\ast <!--\; \ast \; -->\frac{1}{1}=2$

$\frac{3b}{8}:b=\frac{3b}{8}\ast <!--\; \ast \; -->\frac{1}{b}=\frac{3}{8}\ast <!--\; \ast \; -->\frac{1}{1}=\frac{3}{8}$

$\frac{7c^2}{d}:\frac{c}{d^3}=\frac{7c^2}{d}\ast <!--\; \ast \; -->\frac{d^3}{c}=\frac{7c}{1}\ast <!--\; \ast \; -->\frac{d^2}{1}=7c{d}^2$

$\frac{6a}{5b}:\frac{3a^2}{20b^2}=\frac{6a}{5b}\ast <!--\; \ast \; -->\frac{20b^2}{3a^2}=\frac{2}{1}\ast <!--\; \ast \; -->\frac{4b}{a}=\frac{8b}{a}$

$-<!--\; -\; -->\frac{9a}{b^5}:\frac{18a^4}{b^3}=-<!--\; -\; -->\frac{9a}{b^5}\ast <!--\; \ast \; -->\frac{b^3}{18a^4}=-<!--\; -\; -->\frac{1}{b^2}\ast <!--\; \ast \; -->\frac{1}{2a^3}=-<!--\; -\; -->\frac{1}{2a^3{b}^2}$

$a^2:\frac{a}{b^{2}c}=a^2\ast <!--\; \ast \; -->\frac{b^{2}c}{a}=a\ast <!--\; \ast \; -->\frac{b^{2}c}{1}=a{b}^{2}c$

$24a^3:\frac{12a^2}{b}=24a^3\ast <!--\; \ast \; -->\frac{b}{12a^2}=2a\ast <!--\; \ast \; -->\frac{b}{1}=2ab$

$\frac{36a}{c^3}:(4a^{2}c)=\frac{36a}{c^3}\ast <!--\; \ast \; -->\frac{1}{4a^{2}c}=\frac{9}{c^3}\ast <!--\; \ast \; -->\frac{1}{ac}=\frac{9}{a{c}^4}$