a. \(\dfrac{7}{9}+\dfrac{5}{9}\times\dfrac{-11}{23}-\dfrac{5}{9}\times\dfrac{12}{33}\)

b . \(\dfrac{-5}{13}\times\dfrac{3}{17}+-\dfrac{5}{13}\div\dfrac{17}{9}-\dfrac{-5}{13}\times\dfrac{5}{17}\)

\(\dfrac{7}{22}\times\dfrac{5}{3}+\dfrac{7}{22}\times\dfrac{1}{3}-\dfrac{7}{22}\times\dfrac{11}{21}\)

\(\dfrac{-5}{7}\times\dfrac{3}{13}-\dfrac{5}{7}\times\dfrac{10}{13}+1\dfrac{5}{7}\)