1. 脱式计算，能简算的要简算。

(12.5-0.25) ×0.4    12.5÷0.5÷0.4    8÷(1.76-1.36)×1.8

（1）0.25×9.3×4                                 （2）0.83×53＋8.3×4.7

（3）5.4÷1.25÷8                                 （4）（2.1＋6.9÷0.15）÷0.2

28.9÷2.5÷0.4                                 72.6×27.4＋72.6×72.6     

5.98×11－5.98                       （0.58＋0.58＋0.58＋0.58）×2.5

3.78×2.4÷1.8             6.9×99＋6.9                    

2.5×1.6                    8.2÷1.25÷8