Đáp án :
`(2016)/(2017); (2017)/(2018); (2018)/(2019); (2019)/(2020)<4`
Giải thích các bước giải :
`(2016)/(2017)<1<4; (2017)/(2018)<1<4; (2018)/(2019)<1<4; (2019)/(2020)<1<4`
`=>(2016)/(2017); (2017)/(2018); (2018)/(2019); (2019)/(2020)<4`
Vậy : `(2016)/(2017); (2017)/(2018); (2018)/(2019); (2019)/(2020)<4`