3.6-3.6x0.8=3.6×(1-0.8)=0.72
把3.6提出来也就是3.6×(1-0.8)=3.6×0.2=0.72
3.6×(1-0.8)=3.6×0.2=0.72
3.6－3.6×0.8=3.6（1－0.8）=3.6×0.2=0.72
3.6-3.6×0.8=3.6×1-3.6×0.8=3.6×0.2=0.72
