11/12原式=(1-1/2)+(1/2-1/3)+(1/3-1/4)...+(1/10-1/11)+(1/11-1/12)=1-1/12=11/12请到这里看看解题过程：http://hi.baidu.com/sunjiaxing1982/blog/item/8d2d68d5115af3c750da4b75.html
