1. thực hiện phép tính
a. \(\dfrac{-5}{6}\). \(\dfrac{4}{19}\)+\(\dfrac{-7}{12}\).\(\dfrac{4}{19}\)
b. \(7\dfrac{1}{3}\):\(\dfrac{-1}{7}\)-\(\dfrac{1}{3}\):\(\dfrac{-1}{7}\)
c. \(\dfrac{34}{37}\):\(\dfrac{17}{37}\)
d. \(\dfrac{-6}{9}\)+\(\dfrac{-12}{16}\)
e. \(23\dfrac{1}{3}\):\(\dfrac{5}{7}\)-\(23\dfrac{1}{3}\):\(\dfrac{5}{7}\)-\(13\dfrac{1}{3}\):\(\dfrac{5}{7}\)