2⼀11×13+2⼀13×15+2⼀15×17+2⼀17×19+2⼀19

请列出详细的算式!
2025-01-25 03:49:06
推荐回答(1个)
回答1:

2/11×13+2/13×15+2/15×17+2/17×19+2/19
=1/11-1/13+1/13-1/15+1/15-1/17+1/17-1/19+2/19
=1/11+1/19
=30/209