(1又2/3)/(3又1/3)=(5/3)/(10/3)=1/2(2又3/4)/(5又2/4)=(11/4)/(22/4)=1/2…………(98又99/100)/(197又98/100)=(9899/100)/(19798/100)=1/2（1又2/3+2又3/4+3又4/5+...+97又98/99+98又99/100）/(3又1/3+5又2/4+7又3/...