1*1⼀2+1⼀2*1⼀3+1⼀3*1⼀4+1⼀4*1⼀5+1⼀5*1⼀6+1⼀6*1⼀7用简便方法怎么做?

2024-12-18 02:02:12
推荐回答(1个)
回答1:

1*1/2+1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6+1/6*1/7
=1-1/2+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