A)7/30+-12/37+23/30+-25/37 B)1/2+-1/3+1/4+1/-5+1/6+-1/2+1/3+1/-4+1/5

Đáp án:

Giải thích các bước giải:

`a)` `7/30 + (- 12/37) + 23/30 + (- 25/37)`

`= (7/30 + 23/30) + [( - 12/37) + (- 25/37)]`

`= 30/30 + (- 37/37)`

`= 1 + (- 1)`

`= 0`

`b)` `1/2 + (- 1/3) + 1/4 + 1/-5 + 1/6 + (- 1/2 + 1/3 + (1/- 4) + 1/5`

`= [1/2 + (- 1/2)] + [(- 1/3) + 1/3] + [1/4 + (1/- 4)] + [1/- 5 + 1/5] + 1/6`

`= 0 + 0 + 0 + 0 + 1/6`

`= 1/6`

`#Gao`