1/2+1/6+1/12+1/20+1/30+1/42的简便计算

来源：学生作业帮助网编辑：作业帮时间：2024/05/06 07:17:37

1/2+1/6+1/12+1/20+1/30+1/42的简便计算
1/2+1/6+1/12+1/20+1/30+1/42的简便计算

1/2+1/6+1/12+1/20+1/30+1/42的简便计算
=1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7
=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

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