a) (-13)+(+15)-(-7)+(+10)-(-25)
-13+15+7+10+25
2+17+25
44
b) (-26)-(-13)+(+28)-(+55)
-26+13+28-55
-13-27
-40
c) [(-17)-0]-[(+2)-(+0)]-{(-2)-[(+14)-0]}
-17-2+16
-19+16
-3
d) -46-{-69+[-57+(+75)+(-12)]+(-13)}+(+57)
-46-(-69-57+75-12-13)+57
-46-(-126+75-25)+57
-46-(-126+50)-57
-46-(-76)-57
-46+76-57
30-57
-27