文档介绍:-=               +=       -=              +=              -=   -=             +=               -=     1-=                   +=               5×400=+=               187÷1000=                 1+=
 ×10=                75÷10=                    ÷=×7=                ×7=                 ×8=×8=                ×2=                5×=×=              ×=               ×0=
10×=              ×7=                ×100=×4=                ×4=                4×=×8=                ×4=                 ×0= ×50=                30×=                ×3=×2=                ×=              ×=1-=               ×=              ÷=
×4=               -=              ×1=         0×=               ÷5=                 ÷7=                    ÷17=              ÷=               ÷=÷=            ÷4=                ×6= ÷=             ÷=               ×=0÷=              ÷1 =             ÷=÷=             ÷=            ÷=    ÷=             ÷=            ÷=×3 =              ×=             ÷=4÷=               ÷=            ÷=÷=