(1)21.5÷(6.07+2.53) =21.5÷8.6 =2.5 (2)9.6÷0.16÷0.3 =60÷0.3 =200 (3)[20-(90.75÷66+2.2)]×0.6 =[20-(1.375+2.2)]×0.6 =[20-3.575]×0.6 =16.425×0.6 =9.855 (4)0.98×100.1 =0.98×(100+0.1) =0.98×100+0.98×0.1 =98+0.098 =98.098