2013 n＝1 1 n(n+1) = 1 1×2 + 1 2×3 +…+ 1 2013×2014 =1- 1 2 + 1 2 - 1 3 +…+ 1 2013 - 1 2014 =1- 1 2014 = 2013 2014 ．故答案为： 2013 2014 ．
答案顾维20132014
