(3.2+0.128)/0.8=(0.8*4+0.4*0.32)/0.8=(0.8*4+0.4*0.8*0.4)/0.8=4+0.16=4.16
=(0.8×4+0.4×0.32)÷0.8=(0.8×4+0.4×0.8*0.4)÷0.8=4+0.16=4.16
(0.8*4+0.8*0.16)/0.8=0.8(4+0.16)/0.8=4.16
4.16
