原式=(-4又2/3)+3/8+(-5/6)+(-5/8)+3又3/4=[ (-4又2/3) +(-5/6) ] +[ 3/8+(-5/8) ] +3又3/4=[ -(4又2/3 +5/6 ) ] +[ -(5/8-3/8) ] +3又3/4=(-5又1/2 ) +(-1/4) +3又3/4=(-5又1/2)+(3又3/4-1/4)=(-5又1/2)+3又1/2=-(5又1/2-3又1/2)=-2
