Question

{[(120+2×15):75+4]×10^2-40×5}:80

Answer 1

{[( 120+2x15):75 +4 ]x10²-40x5} :80=
{[(120 +30) :75 +4]x100-200}:80=
{[(150:75)+4 ] x100-200}:80=
 [(2+4) x 100-200]:80=
(6x100-200):80=
(600-200):80=
400:80=
5