=1/1×2+1/2×3+1/3×4+1/4×5+1/5×6+1/6×7
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7什么规律能解说一下吗就是1/1×2=1-1/21/2×3=1/2-1/31/3×4=1/3-1/4以此类推我下午去听老师讲一下，晚上帮你设为满意答案，你先解说