递等式计算69.58-17.5+13.42-2.512.5×3.2×2.53.64÷4+4.36×0.2512×（512+725）×25．

Question

递等式计算
69.58-17.5+13.42-2.5                    
12.5×3.2×2.5
3.64÷4+4.36×0.25                        
12×（(5)/(12)+(7)/(25)）×25．

Answer 1

（1）69.58-17.5+13.42-2.5
=（69.58+13.42）-（17.5+2.5）
=83-20
=63；

（2）12.5×3.2×2.5
=12.5×（8×0.4）×2.5
=（12.5×8）×（0.4×2.5）
=100×1
=100；

（3）3.64÷4+4.36×0.25
=3.64×0.25+4.36×0.25
=（3.64+4.36）×0.25
=8×0.25
=2；

（4）12×（(5)/(12)+(7)/(25)）×25
=12×(5)/(12)×25+12×(7)/(25)×25
=125+84
=209．