`99^99 - {1,(3)-[5 . 2^3 - (-7)^2 + 1/3 + 99^9 . (27^4 - 81^3 - 99^90)]}`

`= 99^99 - {4/3 - [5 . 8 - 49 + 1/3 + 99^9 . ((3^3)^4-(3^4)^3-99^90)]}`

`= 99^99 - {4/3 - [40-49+1/4+99^9.  (3^12-3^12-99^90)]}`

`= 99^99 - {4/3 - [40-49+1/3-99^9 . 99^90]}`

`= 99^99 - {4/3-[40-49+1/3-99^99]}`

`= 99^99 - {4/3-40+49+1/3+99^99`

`= 99^99 - 4/3 + 40-49+1/3-99^99`

`= (99^99-99^99)+(-4/3+1/3)+(40-49)`

`= -1-9`

`= -10`