Respostas

2014-03-17T12:30:16-03:00
a)- (+51)+(-51) = 51-51 = 0
b)- -80+30 = -50
c)- -27+30 = +3
d)- (+230)+(-201) = 230 - 201 = +29
e)- -37+37 = 0
f)- +47-59 = -12