Đáp án:
a, `\frac{20192019}{20202020}` = `\frac{2019}{2020}`
`\frac{-2019}{-2020}` = `\frac{2019}{2020}`
Vì `2019` = `2019` nên`\frac{2019}{2020}` =`\frac{2019}{2020}` hay `\frac{20192019}{20202020}` = `\frac{-2019}{-2020}`
Vậy `\frac{20192019}{20202020}` = `\frac{-2019}{-2020}`
b, `\frac{3}{5}` = `\frac{6}{10}`
Vì `6` < `7` nên `\frac{6}{10}` < `\frac{7}{10}` hay `\frac{3}{5}` < `\frac{7}{10}`
Vậy `\frac{3}{5}` < `\frac{7}{10}`
c, `\frac{5}{-14}` = `\frac{-5}{14}` = `\frac{-40}{112}`
`\frac{-7}{16}` = `\frac{-49}{112}`
Vì `-40` > `-49` nên `\frac{-40}{112}` > `\frac{-49}{112}` hay `\frac{5}{-14}` > `\frac{-7}{16}`
Vậy `\frac{5}{-14}` > `\frac{-7}{16}`
d, Ta thấy:
`\frac{20120}{2021}` > `1`
`\frac{2019}{2020}` < `1`
⇒ `\frac{2019}{2020}` < `1` < `\frac{20120}{2021}` hay `\frac{2019}{2020}` < `\frac{20120}{2021}`
Vậy `\frac{2019}{2020}` < `\frac{20120}{2021}`.
