下面各题怎样简便就怎样计算.
9.9×25                                 0.75×0.5×4×0.2
1.25×32×0.25                              8.12×4+1.88×4
0.32×13.4﹣0.32×3.4                       3.84×99+3.84
2.009×390+20.09×41+200.9×2              （9.57+9.57+9.57+9.57 ）×25．