合理计算
8.6×10.1                          78.1﹣7.7÷0.7×5.2          〔（8.1﹣5.6）×0.9﹣1〕×0.4
8.25×4.08+0.75×4.08+4.08         1.25×32×2.5                  8.1÷2+1.9÷2．