计算-1/2-1/6-1/12-1/20-1/30-1/42

问题描述:

计算-1/2-1/6-1/12-1/20-1/30-1/42

原式=-(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)=-6/7