1. thực hiện phép tính
a. \(\dfrac{3}{4}\)+\(\dfrac{6}{12}\)-\(\dfrac{5}{24}\)
b.\(\dfrac{-5}{7}\).\(\dfrac{2}{13}\)-\(\dfrac{5}{7}\).\(\dfrac{11}{13}\)+\(\dfrac{5}{7}\)
c. \(\dfrac{27}{23}\)+\(\dfrac{5}{21}\)+\(\dfrac{1}{2}\)-\(\dfrac{4}{23}\)+\(\dfrac{16}{21}\)
d. \(\dfrac{15}{34}\)+\(\dfrac{7}{21}\)+\(\dfrac{19}{34}\).\(\dfrac{20}{15}\)+\(\dfrac{3}{7}\)