7又2/9*1.1-6.81*9/97+68.1/(5又2/19)=65/9*1.1-6.81*9/97+68.1*19/97=71.5/9+6.81/97*(19-9)=71.5/9+68.1/97=(71.5*97+68.1*9)/(9*97)=(6935.5+68.1)/873=7003.6/873=8.02245