10º) Resolva as somas algébricas.
a) - 8- 12 +31 =
d) - 18 + 6-23 + 30
b) -20 -7 -12 + 30 =
e) + 30 - 30 + 40 - 80 =
c) -33 +34-35 + 36 =
f) - 15 + 45-90 =
-​