Question

1/6+1/12+1/20+1/30+1/42+1/56+1/72 找规律并计算

Answer 1

原式=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)+(1/8-1/9)=1/2-1/9=7/18