Question

12+(-1)×{[-9:(-1-8)×(-1)]}

Answer 1

= 12 + (-1) . {[ - 9 : (- 1 - 8) × (-1)]}
= - 12 . {[ - 9 : (-9) .(-1)]}
= - 12 . {[ 1.(-1)]
= - 12 . { - 1}
= 12