1⼀6+1⼀12+1⼀20+1⼀30+1⼀42+1⼀56+1⼀72+1⼀90=?

2024-12-18 02:30:08
推荐回答(1个)
回答1:

0.4 就这个
=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+1/9-1/10
=1/2-1/10
=2/5