Respostas

2014-02-09T14:46:28-02:00
2014-02-09T14:49:15-02:00
-12 + (-6) - (8 - 5) = -12 + (-6) - (3) =
-12 + (-6 - 3) =
-12 + (-9) =
-12 - 9 =  - 21