Respostas

2014-04-13T18:14:29-03:00
(-6).(+5)-(-4).(+3)
-30 - ( -12)
-30 +12
-18
2014-04-13T18:22:19-03:00
(-6).(+5)-(-4).(+3)=
-30-(-12)=
-30+12=
-18