[tex]\frac{\not{4}^1}{7} \cdot \frac{3}{\not{20}_5}=\frac{3}{35} \\\\ \frac{\not{12}^3}{\not{25}_5} \cdot \frac{\not{5}^1}{\not{8}_2}=\frac{3}{10} \\\\ \frac{\not{4}^2}{\not{21}_3} \cdot \frac{\not{7}^1}{\not{20}_{\not{2}_1}} \cdot \frac{\not{10}^1}{11} =\frac{2}{33}[/tex]
