Cứuuuuuuuuuuuuu với .

`@``text{Bơ}`

`a) 5/16 - (7/15 - 3/16) + 17/30`

`= 5/16 - 7/15 + 3/16 + 17/30`

`= (5/16 + 3/16) + (-7/15 + 17/30)`

`= 1/2 + (-14/30 + 17/30)`

`= 1/2 + 1/10`

`= 5/10 + 1/10`

`= 6/10`

`= 3/5`

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

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

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

`= (3/6 - 5/6) + (15/20 + 16/20)`

`= -1/3 + 31/20`

`= -20/60 + 93/60`

`= 73/60`