\(A=\left(\dfrac{2}{7}.\dfrac{1}{4}-\dfrac{1}{3}.\dfrac{2}{7}\right):\left(\dfrac{2}{7}.\dfrac{3}{9}-\dfrac{2}{7}.\dfrac{2}{5}\right)\)

    \(=\left(\dfrac{2}{7}.\left(\dfrac{1}{4}-\dfrac{1}{3}\right)\right):\left(\dfrac{2}{7}.\left(\dfrac{1}{3}-\dfrac{2}{5}\right)\right)\)

    \(=\left(\dfrac{2}{7}.\dfrac{-1}{12}\right):\left(\dfrac{2}{7}.\dfrac{-1}{15}\right)\)

    \(=\dfrac{-1}{12}:\dfrac{-1}{15}\)

    \(=\dfrac{5}{4}\)

\(A=\dfrac{3}{5}.\dfrac{6}{7}+\dfrac{3}{7}:\dfrac{5}{3}-\dfrac{2}{7}:1\dfrac{2}{3}\)

    \(=\dfrac{3}{5}.\dfrac{6}{7}+\dfrac{3}{7}.\dfrac{3}{5}-\dfrac{2}{7}.\dfrac{3}{5}\) 

    \(=\dfrac{3}{5}.\left(\dfrac{6}{7}+\dfrac{3}{7}-\dfrac{2}{7}\right)\)

    \(=\dfrac{3}{5}.1\)

    \(=\dfrac{3}{5}\)

\(B=\left(-13.\dfrac{2}{5}+\dfrac{-2}{9}:2\dfrac{1}{2}+\dfrac{2}{5}.\dfrac{11}{9}\right).2\dfrac{1}{2}\)

    \(=\left(-13.\dfrac{2}{5}+\dfrac{-2}{9}.\dfrac{2}{5}+\dfrac{2}{5}.\dfrac{11}{9}\right).\dfrac{5}{2}\)

    \(=\left(-13+\dfrac{-2}{9}+\dfrac{11}{9}\right).\dfrac{2}{5}.\dfrac{5}{2}\)

    \(=\left(-13+\dfrac{-2}{9}+\dfrac{11}{9}\right).1\)

    \(=\left(-13+\left(\dfrac{-2}{9}+\dfrac{11}{9}\right)\right).1\)

    \(=\left(-13+1\right).1\)

    \(=-12\)

\(C=\left(\dfrac{-4}{5}+\dfrac{5}{7}\right):\dfrac{2}{3}+\left(\dfrac{-1}{5}+\dfrac{2}{7}\right):\dfrac{2}{3}\)

    \(=\left(\dfrac{-4}{5}+\dfrac{5}{7}\right).\dfrac{3}{2}+\left(\dfrac{-1}{5}+\dfrac{2}{7}\right).\dfrac{3}{2}\)

    \(=\dfrac{3}{2}.\left(\left(\dfrac{-4}{5}+\dfrac{5}{7}\right)+\left(\dfrac{-1}{5}+\dfrac{2}{7}\right)\right)\)

    \(=\dfrac{3}{2}.\left(\left(\dfrac{-4}{5}+\left(\dfrac{-1}{5}\right)\right)+\left(\dfrac{5}{7}+\dfrac{2}{7}\right)\right)\)

    \(=\dfrac{3}{2}.\left(-1+1\right)\)

    \(=\dfrac{3}{2}.0=0\)

\(D=\dfrac{4}{9}:\left(\dfrac{1}{15}-\dfrac{2}{3}\right)+\dfrac{4}{9}:\left(\dfrac{1}{11}-\dfrac{5}{22}\right)\)

    \(=\dfrac{4}{9}:\dfrac{-3}{5}+\dfrac{4}{9}:\dfrac{-3}{22}\)

    \(=\dfrac{4}{9}.\dfrac{-5}{3}+\dfrac{4}{9}.\dfrac{-22}{3}\)

    \(=\dfrac{4}{9}.\left(\dfrac{-5}{3}+\dfrac{-22}{3}\right)\)

    \(=\dfrac{4}{9}.\left(-9\right)\)

    \(=-4\)

\(P=\dfrac{2}{3}-\left(\dfrac{-1}{4}\right)+\dfrac{3}{5}-\dfrac{7}{45}-\left(\dfrac{-5}{9}\right)+\dfrac{1}{12}+\dfrac{1}{35}\)

    \(=\dfrac{2}{3}+\dfrac{1}{4}+\dfrac{3}{5}+\left(\dfrac{-7}{45}\right)+\dfrac{5}{9}+\dfrac{1}{12}+\dfrac{1}{35}\)

    \(=\left(\dfrac{2}{3}+\dfrac{1}{4}+\dfrac{1}{12}\right)+\left(\dfrac{-7}{45}+\dfrac{5}{9}\right)+\dfrac{3}{5}+\dfrac{1}{35}\)

    \(=1+\dfrac{2}{5}+\dfrac{3}{5}+\dfrac{1}{35}\)

    \(=1+\dfrac{14}{35}+\dfrac{21}{35}+\dfrac{1}{35}\)

    \(=\dfrac{49}{35}+\dfrac{21}{35}+\dfrac{1}{35}\)

    \(=\dfrac{70}{35}+\dfrac{1}{35}\)

   \(=\dfrac{71}{35}\)

\(Q=\left(5-\dfrac{3}{4}+\dfrac{1}{5}\right)-\left(6+\dfrac{7}{4}-\dfrac{8}{5}\right)-\left(2-\dfrac{5}{4}+\dfrac{16}{5}\right)\)

    \(=5-\dfrac{3}{4}+\dfrac{1}{5}-6-\dfrac{7}{4}+\dfrac{8}{5}-2+\dfrac{5}{4}-\dfrac{16}{5}\)

    \(=5+\left(\dfrac{-3}{4}\right)+\dfrac{1}{5}+\left(-6\right)+\left(\dfrac{-7}{4}\right)+\dfrac{8}{5}+\left(-2\right)+\dfrac{5}{4}+\left(\dfrac{-16}{5}\right)\)

    \(=\left(5+\left(-6\right)+\left(-2\right)\right)+\left(\dfrac{1}{5}+\dfrac{8}{5}+\left(\dfrac{-16}{5}\right)\right)+\left(\left(\dfrac{-3}{4}\right)+\left(\dfrac{-7}{4}\right)+\dfrac{5}{4}\right)\)

    \(=-3+\left(\dfrac{-7}{5}\right)+\left(\dfrac{-5}{4}\right)\)

    \(=\dfrac{-60}{20}+\left(\dfrac{-28}{20}\right)+\left(\dfrac{-25}{20}\right)\)

    \(=\dfrac{-88}{20}+\left(\dfrac{-25}{20}\right)\)

    \(=\dfrac{-113}{20}\)

\(A=\left(\dfrac{1}{3}-\dfrac{8}{15}-\dfrac{1}{7}\right)+\left(\dfrac{2}{3}+\dfrac{-7}{15}+1\dfrac{1}{7}\right)\)

    \(=\dfrac{1}{3}-\dfrac{8}{15}-\dfrac{1}{7}+\dfrac{2}{3}+\dfrac{-7}{15}+1\dfrac{1}{7}\)

    \(=\dfrac{1}{3}+\left(\dfrac{-8}{15}\right)+\left(\dfrac{-1}{7}\right)+\dfrac{2}{3}+\left(\dfrac{-7}{15}\right)+\dfrac{8}{7}\)

    \(=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(\left(\dfrac{-8}{15}\right)+\left(\dfrac{-7}{15}\right)\right)+\left(\left(\dfrac{-1}{7}\right)+\dfrac{8}{7}\right)\)

    \(=1+\left(-1\right)+1\)

    \(=1\)

\(B=0,25+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+1\dfrac{1}{4}\right)\)

    \(=\dfrac{1}{4}+\dfrac{3}{5}-\left(\dfrac{1}{8}-\dfrac{2}{5}+\dfrac{5}{4}\right)\)

    \(=\dfrac{1}{4}+\dfrac{3}{5}-\dfrac{1}{8}+\dfrac{2}{5}-\dfrac{5}{4}\)

    \(=\dfrac{1}{4}+\dfrac{3}{5}+\left(\dfrac{-1}{8}\right)+\dfrac{2}{5}+\left(\dfrac{-5}{4}\right)\)

    \(=\left(\dfrac{1}{4}+\left(\dfrac{-5}{4}\right)\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{-1}{8}\right)\)

    \(=-1+1+\left(\dfrac{-1}{8}\right)\)

    \(=\dfrac{-1}{8}\)