53.5*35.3+5.35*567-53.5
=53.5*35.3+53.5*56.7-53.5
=53.5*(35.3+56.7-1)
=53.5*(90+1)
=53.5*90+53.5
=4815+53.5
=4868.5前面都能看懂，只是为什么-1不太明白，请教！-53.5 提取53.5 出来就是 -1(35.3+56.7-1)=91=90+1