Đáp án:
`1`
Giải thích các bước giải:
`(2020xx2021-2045)/(1995+2019xx2020`
`=(2020xx2021-2021-24)/(1995+2019xx2020)`
`=(2019xx2021-24)/(1995+2019xx2020`
`=(2019xx(2020+1)-24)/(1995+2019xx2020`
`=(2019xx2020+2019-24)/(1995+2019xx2020`
`=(2019xx2020+1995)/(1995+2019xx2020`
`=1`