Question

resolva:-20+{-5+[(-12+30)+(-4-7)]}

Answer 1

-20+{-5+[18+(-11)]
-20+{-5+[18-11]
-20+{-5+7}
-20+2
-18

Answer 2

-20 + {-5 +[(-12+30) + (-4-7)]}∴

-20 + {-5+[(+18) + (-11)]}∴

-20 + {-5+ [7]}∴

-20 + {-5+7}∴    -20 + {+2}∴

-20 +2 = -18