15又1/2-3又1/5-2又1/4=15.5-3.2-2.25=10.05=10又1/202/15+1又7/9=2/15+16/9=6/45+35/45=41/4510又1/3-3又1/5=10又5/15-3又3/15=7又2/1545又8/11-(30又2/5+8又3/11)=45又8/11-30又22/55-8又3/11=37又25/55-30又22/55...