因为1/4=4/16
所以(7/16-1/4)=3/16
3/16÷1/2=6/16+15/16=21/16*8=21/2=10.5
10.5/9=21/18=7/6
=[(7/16-4/16)÷1/2+15/16]×8/9=[3/16÷1/2+15/16]×8/9=[3/16×2+15/16]×8/9=[6/16+15/16]×8/9
=21/16×8/9=7/6=1.16666666.................................................................................................6.