用递等式计算．（写出必要的计算过程，能简便计算的用简便方法计算）
7.9×12.5                                   25.38﹣1.43﹣4.38﹣4.57
90+10÷0.4×2.5                             0.8×0.4×（7.6×1.25）×2.5
2.3×0.48+0.48×8.7﹣0.12×4；              0.1﹣0.1×[0.01÷（；1﹣0.9）]．