看见125就要想到8或4.解法一4.92×125=0.615×8×25=0.615×(8×25)=0.615×1000=615解法二4.92×125=(4+0.92)×125=4×125+0.92×125=500+(1-0.08)×125=500+125×1-0.08×125=500+125-10=615
5×125-0.08×125=625-10=615
5✘125-0.08✘125