Đáp án:
$\\$
`a,`
`-3 1/4 + 4 1/2 : 3/4`
`= (-13)/4 + 9/2 . 4/3`
`= (-13)/4 + 6`
=11/4`
`b,`
`(-3,25 + 2 1/3) : 8/3`
`= ( (-13)/4 + 7/3) . 3/8`
`= (-11)/12 . 3/8`
`= (-11)/32`
`c,`
`36/5 . (45/4 - 25/12 + 5/18)`
`= 36/5 . (55/6 + 5/18)`
`= 36/5 . 85/9`
`= 68`
`d,`
`2018/2019 . 2020/2021 - 2018/2021 . 1/2019`
`= 2018/2019 . 2020/2021 - 2018/2019 . 1/2021`
`= 2018/2019 . (2020/2021 - 1/2021)`
`= 2018/2019 . 2019/2021`
`= 2018/2021`