巧算 12*14⼀2+12*16⼀2+16*18⼀2+18*20⼀2+20⼀1

2024-12-15 07:05:10
推荐回答(1个)
回答1:

=1/12-1/14+1/14-1/16+1/16-1/18+1/18-1/20+ 1/20
=1/12