A=−785+{−801−[184−(184+801+785)]}A=-785+{-801-[184-(184+801+785)]}
⇔A=−785−801−184+184+801+785⇔A=-785-801-184+184+801+785
⇔A=(184−184)+(801−801)+(785−785)⇔A=(184-184)+(801-801)+(785-785)
⇔A=0⇔A=0
B=−126−{790+[−157−(126−790−157)]}B=-126-{790+[-157-(126-790-157)]}
⇔B=−126−790+157+126−790−157⇔B=-126-790+157+126-790-157
⇔B=−790−790⇔B=-790-790
⇔B=−1580