2⼀1-6⼀1-12⼀1-20⼀1-30⼀1-42⼀1=?

2/1减6/1减12/1减20/1减30/1减42/1=?简算啊急!!要步骤!!
2025-02-23 22:16:11
推荐回答(2个)
回答1:

七分之一

回答2:

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