Question

}-20+40+[+50-20)+[-30+10]} tem que responder

Answer 1

{-20 + 40 + [ + 50 - 20 ) + [-30 + 10]}
{-20 + 40 + [ + 30) + [ -20]}
{ -20 + 40 + [ +30 - 20]}
{ -20 + 40 + [ +10}
{ - 20 + 40 + 10}
-20 + 50 = +30