1. Tính a) 5 $\frac{5}{2}$ – $\frac{4}{6}$ + 1 b) – $\frac{2}{9}$ + $\frac{1}{6}$ – $\frac{5}{9}$

`a) 5/2 – 4/6 + 1`

`= 15/6 – 4/6 + 6/6`

`=\frac{15 – 4 + 6}{6}`

`= 17/6`

`b) -2/9 + 1/6 – 5/9`

`= ( -2/9 – 5/9) + 1/6`

`= -7/9 + 1/6`

`= -14/18 + 3/18`

`= -11/18`