liczby całkowite
obliczyc;
a)(-2)+(-8)-(+6)-(-4)=
b)(+12)-(-16)-(+6)+(+20)=
c)-20-(-5)+(-17)-(-3)=
d)(-4+7)-(-10-12)=
e)-(-11+14)-(16-13)=
f)-(12-6)+(4-9)=