`1)` `3/7` + `(-5/2)` + `(-3/5)`
= `3/7 - 5/2 - 3/5`
= `-29/14 - 3/5`
= `-187/70`
`2)` `-1/24 - [ 1/4 - ( 1/2 - 7/8 )]`
= `-1/24 - ( 1/4 + 3/8 )`
= `-1/24 - 5/8`
= `-2/3`
`3)` `( 5/7 - 7/5 ) [ 1/2 - ( -2/7 - 1/10 )`
= `-24/35 ( 1/2 + 27/70 )`
= `-24/35 . 31/35`
= `-744/1225`