8/9+5/6+1/9
=31/18+1/9
=11/6
8/9+5/6+1/9=8/9+1/9+5/6=1+5/6=11/6所以结果是11/6
8/9+5/6+1/9=(8/9+1/9)+5/6=1+5/6=11/6