9又100分之81*0.1+1分之2*98又10分之1+0.049*981
=9.81x0.1+0.5x98.1+0.049x100x9.81
=9.81x0.1+9.81x10x0.5+9.81x4.9
=9.81x(0.1+5+4.9)
=9.81x10
=98.1