`\frac{1000}{1009} . \frac{-2018}{2019} + \frac{19}{2018} . \frac{-2018}{2019} +\frac{1}{2020}`
`=1000. \frac{-2}{2019} + 19 . \frac{-1}{2019} + \frac{1}{2020}`
`= \frac{-2020}{2019} + \frac{-19}{2019} + \frac{1}{2020}`
`= \frac{-2019}{2019} + \frac{1}{2020}`
`=-1 + \frac{1}{2020}`
`=\frac{-2019}{2020}`