1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110
找规律吧：得数应该是10/11
1/2+1/6=2/3
2/3+1/12=3/4
3/4+1/20=4/5
……每次分母,分子加1,总共10次
就像一个正方形,1/4后再1/4……想想……
补充：1/2+1/6……+1/1020=1-1/2+1/2-1/3+1/3-1/4……+1/10-1/11
=1-1/11
=10/11

1/2+1/6……+1/110
=1/2+1/2*3+1/3*4+……+1/10*11
=1-1/2+1/2-1/3+1/3-1/4……+1/10-1/11
=1-1/11
=10/11
分数列项基础题目