1 /2+1/6+1/12+1/20+1/30+1/42 用简便方法计算这道题_数学解答

1 /2+1/6+1/12+1/20+1/30+1/42 用简便方法计算这道题

人气：385 ℃　时间：2020-04-03 20:06:54

解答

1 /2+1/6+1/12+1/20+1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7