II. TỰ LUẬN

- Hướng dẫn giải

a. Ta có:

$$\begin{gathered} \left(\frac{9}{16}-\frac{5}{8}+\frac{3}{4}\right):\frac{11}{32} \\ =\left(\frac{9-10+12}{16}\right).\frac{32}{11} \\ =\frac{11}{16}.\frac{32}{11} \\ =2 \end{gathered}$$

b. Ta có

$$\begin{gathered} \frac{1000}{1009}.\frac{-2018}{2019}+\frac{19}{2018}.\frac{-2018}{2019}+\frac{1}{2020} \\ =\frac{-2018}{2019}\left(\frac{1000}{1009}+\frac{19}{2018}\right)+\frac{1}{2020} \\ =\frac{-2018}{2019}.\left(\frac{2000+19}{2018}\right)+\frac{1}{2020} \\ =\frac{-2018}{2019}.\frac{2019}{2018}+\frac{1}{2020} \\ =-1+\frac{1}{2020} \\ =\frac{-2019}{2020} \end{gathered}$$