5.8x99+5.8=5.8x(99+1)=5.8x100=580希望能帮到你
5.8x(99十1)=5.8x1O0=58o
5.8x99+5.8 =5.8x(99+1)=5.8x100=580
5.8x99+5.8=5.8×(99+1)=5.8×100=580