=9.85*99+9.85*1=9.85(99+1)=98.5
9.85×99+98.5×0.1=9.85×99+9.85×1=9.85×(99+1)=9.85×100=985
=9.85X(99十1)=9.85X100=985
9.85×(99+1)=985