17- calcule o valor das expressões:
a) (-10)-(-8)+(-2)-(+5)+(-3)=
b) (20-25)-5+(18-7+5)=
c) 8-(-6)+(-5)+(8-3+5-10+12)=
d) (+3-10-5+7-12)-(-8+3-4+6-18)=
e) +10+(-6-3)-4-(+8-5)-(-7+12)=
f) +14-21+45-6-8+35-50+21=
g) +8-5+3-4+7-2+6=