Question

Bài 4 : Tính nhanh

\(\dfrac{-1}{24}-\left[\dfrac{1}{4}-\left(\dfrac{1}{2}-\dfrac{7}{8}\right)\right]\)

Answer 1

`(-1)/24 -[1/4 -(1/2 -7/8)]`

`=(-1)/24-(1/4 -1/2 +7/8`

`=(-1)/24 -(2/8 -4/8 +7/8)`

`=(-1)/24-5/8`

`=(-1)/24 - 15/24`

`=-16/24`

`=-2/3`