1/(1×2)+1/(2×3)+1/(3×4)……+1/(98×99)
问题描述：
1/(1×2)+1/(2×3)+1/(3×4)……+1/(98×99)
答
1/(1*2)=1-1/2
1/(2*3)=(1/2)-(1/3)
1/(3*4)=(1/3)-(1/4)
以此类推
最后答案为1-1/99=98/99