Using a calculator, evaluate the following expression and round off to the nearest $3$ decimal places:  $16.7-\sqrt[3]{\frac{(-4.56)^{2}-(8.1)^{3}}{7.2^{3}}\div\left[-\sqrt{6\frac{3}{4}}-(-30.15)\right]}$ 
Overseas Competition->Knowledge Point->Calculation Modules