1.25*2.5*0.64*0.5的简便算法

0.64=0.8*0.8
原式=（1.25*0.8）*[（0.8*2.5）*0.5]
=1*（2*0.5）
=1

1.25*2.5*0.64*0.5=1.25*0.8*2.5*0.5*0.8=1

2.5*0.5是1.25，再乘1.25就是5/4的平方为25/16，16再与0.64约分，就成了0.04*25，结果是1

(1.25*0.8)(2.5*0.8*0.5)

1.25*0.8*2.5*0.4*1=1

1.25*2.5*0.64*0.5
=1.25*2.5*（2*0.4*0.8)*0.5
=(1.25*0.8)*(2.5*0.4)*(0.5*2)
=1*1*1
=1