giúp mình nhanh nhất có thể nha cảm ơn

Đáp án `+` Giải thích các bước giải:

`b) 3/7 + (- 5/2) + (- 3/7)`

`= [3/7 + (- 3/7)] + (- 5/2)`

`= 0 + (-5/2)`

`= - 5/2`

`c) 29/20 + 17/30 - 9/20 + 13/30 - 1/2`

`= (29/20 - 9/20) + (17/30 +13/30) - 1/2`

`= 20/20 + 30/30 -1/2`

`= 1 + 1 - 1/2` 

`= 4/2 - 1/2`

`= 3/2`

`d) 1 5/13 - 0,25 - (2 5/9 + 18/13 - 1/4)`

`= 1 +5/13 - 1/4 - [(2 + 5/9) + 18/13 - 1/4]`

`= 1 + 5/13 - 1/4 - 2 - 5/9 - 18/13 + 1/4`

`= (1 - 2) + (5/13 - 18/13) - (1/4 - 1/4) - 5/9`

`= -1 + -13/13 - 0 - 5/9`

`= - 2 - 5/9`

`= - 18/9 - 5/9`

`=  - 23/9`

`e) A = (4- 1/4+ 2/3) + (5+4/3 - 6/5)- (6+ 7/4 +4/5)`

`A = 4 - 1/4 + 2/3 + 5 +4/3 -6/5 - 6 - 7/4 - 4/5`

`A = (4 + 5 - 6) - (1/4 + 7/4) + (2/3 + 4/3) -(6/5 + 4/5)`

`A = 3 - 8/4 + 6/3 - 10/5`

`A = 3 - 2 +2-2`

`A = 1`

Vậy `A = 1`

`#Gao`