原式=|-3又1/2+2又1/3|-(5又1/3-3/4)=3又1/2-2又1/3-5又1/3+3/4=(3又1/2+3/4)-(2又1/3+5又1/3)=4又1/4-7又2/3=-(7又2/3-4又1/4)=-[(7-4)+(2/3-1/4)]=-(3+5/12)=-3又5/12-6又3/10+1.4=-4.9