图
-1又2分之1+正一又1/4加(-2)又1/2减(-3)又4分之1-正一又四分之一=-(1+1/2)+(1+1/4)-(2+1/2)+(3+1/4)-(1+1/4)=1+1/4+3+1/4-(1+1/2+2+1/2+1+1/4)=4+1/2-5-1/4=-(1-1/2+1/4)=-(1-1/4)=-3/4=-4分之3