递等式计算（能简便的要简便计算）
1.25×3.2×0.8        14.5×102                  4.7×4.7+4.7+4.7×4.3
9.6÷0.4×0.25        8.68﹣8.68÷0.56×0.5      29.7÷（5.85÷0.65）