Giúp dfi ạ làm ownnn

`a, 3,5 + |-1/2| - |-3,5| + 1/2`

`= 7/2 + 1/2 - 3,5 + 1/2`

`= 7/2 + 1/2 - 7/2 + 1/2`

`= (7/2 - 7/2) + (1/2 + 1/2)`

`= 0 + 1`

`= 1`

___________________

`b, |-10,5| - |5,75| + |9 1/2| + |-5 3/4|`

`= 10,5 - 5,75 + |19/2| + |-23/4|`

`= 4,75 + 19/2 + 23/4`

`= 19/4 + 61/4`

`= 20`