\[\displaystyle O = \frac{2\tfrac{3}{10}-1\tfrac{1}{5}}{1\tfrac{1}{2}-3\tfrac{1}{2}\cdot\tfrac{2}{7}+\tfrac{3}{4}}+\frac{1}{2\tfrac{3}{4}+\tfrac{3}{8}}+\frac{1\tfrac{2}{3}\cdot 2\tfrac{2}{5}}{3\tfrac{4}{5}+2\tfrac{1}{2}\cdot\tfrac{2}{5}+\tfrac{1}{5}}-2\]

\[\displaystyle P = \frac{9}{10}+\left[\left(4\tfrac{2}{3}-\frac{14-\tfrac{1}{3}}{3}\right)\cdot 4\tfrac{1}{2}-\frac{1\tfrac{2}{5}+\tfrac{1}{3}}{8\tfrac{1}{2}+\tfrac{1}{6}}\right]\cdot 1\tfrac{2}{3}:5\]

\[\displaystyle Q = \frac{\left(13\tfrac{3}{5}-6\tfrac{14}{15}\right)\cdot 4\tfrac{1}{2}}{6\tfrac{5}{9}-5\tfrac{1}{18}}-\frac{\left(1\tfrac{2}{5}-1\tfrac{1}{6}\right):\tfrac{7}{10}}{\left(1\tfrac{1}{3}-1\tfrac{1}{7}\right):\tfrac{2}{7}}:6\tfrac{1}{2}\cdot\frac{2^4\cdot5^3\cdot10}{2^5\cdot5^5}\]

\[\displaystyle R = \frac{1}{6}+\frac{\left(10-5\tfrac{3}{4}\right):2\tfrac{5}{6}+5\tfrac{1}{2}}{\left(2\tfrac{1}{3}+\tfrac{5}{12}+\tfrac{1}{2}\right)\cdot\tfrac{8}{13}}+\frac{\left(14-9\tfrac{5}{8}\cdot\tfrac{8}{11}\right):3\tfrac{1}{2}}{\left(7+1:\tfrac{7}{5}\right)\cdot\tfrac{7}{9}}\]

\[\displaystyle S = \frac{2}{3}+\dfrac{\dfrac{12\cdot1\tfrac{1}{12}-9:6}{12:8+2\tfrac{2}{9}\cdot4\tfrac{1}{2}}}{\dfrac{1:4+5:3}{1\tfrac{7}{9}\cdot\tfrac{9}{8}-1\tfrac{3}{4}\cdot\tfrac{7}{9}}}\]