该题规律为1/1*2+1/2*3+1/3*4+...+1/9*10+1/10*11+1/11*12=1-1/2+1/2-1/3+1/3-1/4+...+1/9-1/10+1/10-1/11+1/11-1/12=1-1/12=11/12