(1+1/11+1/樱耐13+1/17)(1/11+1/13+1/17+1/19)-(1+1/裤颂毁11+1/13+1/17+1/19)(1/11+1/13+1/17)=(1/11+1/13+1/17+1/19)+(1/11+1/13+1/17)(1/11+1/13+1/17+1/19)-(1/11+1/13+1/17)-(1/胡备11+1/13+1/17)(1/11+1/13+1/17+1/19)=1/19