2/1+6/1+12/1+20/1+······+9702/1+9900/1

你好!
首先纠正,二分之一应该表示为1/2,六分之一应该表示为1/6
1/2 + 1/6 + 1/12 +1/20 + ······+ 1/9702 + 1/9900
=1/1×2 + 1/2×3 + 1/3×4 + 1/4×5 ······+ 1/98×99 + 1/99×100
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5 ······+1/98-1/99+1/99-1/100
=1 - 1/100
=99/100
希望我的回答对你有所帮助.

2/1+6/1...?
还是1/2+1/6+.....

2/1+6/1+12/1+20/1+······+9702/1+9900/1
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……1/98-1/99+1/99-1/100
=1-1/100
=99/100