bài 1)
1)
a) `-7/12` + `3/4` - `5/3`
= `-7/12` + `9/12` - `20/12`
= `2/12` - `20/12`
= `-18/12`
= `-3/2`
b)
`-15/18` + `1/-6` + `25%`
= `-5/6` + `-1/6` + `1/4`
= ` -6/6` + `1/4`
= - 1 + `1/4`
= `-4/4` + `1/4`
= `-3/4`
2)
a)
15 `5/7` + 3 `1/3` - 4 `5/7`
= `110/7` + `10/3` - `33/7`
=(`110/7`- `33/7`) + `10/3`
= `77/7` + `10/3`
= `11` + `10/3`
=`33/3` + `10/3`
= `43/3`
b) `-5/7` . `2/11` + `-5/7` . `9/11` + 1 `5/7`
= `-5/7` . ( `2/11` + `9/11`) + 1`5/7`
= `-5/7` . `11/11` + `12/7`
= `-5/7` . 1 + `12/7`
= `-5/7` + `12/7`
= `7/7`
= `1`