a) -92-17+42+(-70+81-1)= -109+42+10=-109+52=-57
b)6-[2+(-8)-1]=6-(2-9)=6-(-7)=6+7=13
c)77-204+(245-475)-(41-242-156)=-127-230+357=-357+357=0
d)5- {2-[1-(-2)]}-6=5-(2-(1+2))-6=-1-(2-3)=-1-(-1)=-1+1=0
e)-400-[-245+(185-6 100)]=-400-(-6160)=-400+6160=5760