4.8-4.8×0.9=4.8×(1-0.9)=4.8×0.1=0.489.6×28.5+0.285×40简便运算怎么算？要写过程。9.6×28.5+0.285×40=9.6×28.5+28.5×0.4=28.5×(9.6+0.4)=28.5×10=285