(a-c)-b=a-c-b
a+b+c
c-(a+b+d)=c-a-b-d
40+(56-43)=40+13=53
16+(20+3)=16+23=39
(80-40)+24=40+24=64
40+(56-43)=53
16+(20+3)=38
(80-40)+24=64
40+(56-43)=40+56-43=53
16+(20+3)=16+20+3=39
(80-40)+24=80-40+24=64
(a-c)-b=a-c-b
a+b+c
c-(a+b+d)=c-a-b-d
40+(56-43)=40+13=53
16+(20+3)=16+23=39
(80-40)+24=40+24=64
40+(56-43)=53
16+(20+3)=38
(80-40)+24=64
(a-c)-b=a-c-b
a+b+c
c-(a+b+d)=c-a-b-d
40+(56-43)=40+56-43=53
16+(20+3)=16+20+3=39
(80-40)+24=80-40+24=64