(-1/2)+(1/3)+(-1/4)+(1/9)+(1/8)+(-4/9) =

问题描述:

(-1/2)+(1/3)+(-1/4)+(1/9)+(1/8)+(-4/9) =

-1/2)+(+1/3)+(-1/4)+(+1/9)+(+1/8)+(-4/9)=(-1/2-1/4+1/8)+(1/3+1/9-4/9)=-5/8+0=-5/8