Respostas

2014-03-12T21:19:53-03:00
A) 0-(-17)= 
      = +17

b)(-9).(+16)=
   -9(+16)=
  = -144

c)(+13)-(+20)=
   13-20=
    = -7 

2014-03-12T21:21:07-03:00
Calcule
0-(-17)=  + 17    
b)(-9).(+16) = -144
c)(+13)-(+20)=
13-20
-7