(-19)*91+91*(-81)=91*(-19-81)=91*(-100)=-9100(-36)*200又18分之7=(-36)*(200+7/18)=-7200-14=-7214(-270)*4分之1+0.25*21.5+(-8又2分之1)*(-25%)=(-270)*0.25+0.25*21.5+8.5*0.25=0.25*(-270+21.5+8.5)=0.25*(-24...