1/2-(2/3)^9:(2/3)^7+5/6

`\color{#1c1c1c}{\text{I}}^(\color{#363636}{\text{t}}^(\color{#4f4f4f}{\text{s}}^(\color{#696969}{\text{m}}^(\color{#828282}{\text{e}}^(\color{#9c9c9c}{\text{F}}^(\color{#b5b5b5}{\text{r}}^(\color{#cfcfcf}{\text{e}}^\color{#eee9e9}{\text{d}})))))))`

    `1/2 - (2/3)^9 : (2/3)^7 + 5/6`

`= 1/2 - (2/3)^(9 - 7) + 5/6`

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

`= 1/2 - 4/9 + 5/6`

`= 9/18 - 8/18 + 15/18`

`= (9 - 8 + 15)/18`

`= 8/9`