0.25×3.2×1.25=0.25×4×0.8×1.25=（0.25×4）×（0.8×1.25）=1×1=1
=(0.25*4)*(1.25*0.8) =1 + 1 =2
0.25×3.2×1.25=1/4x4x8/10x5/4=1
