综上所述,答案如下
" d' b! K0 N" H! b0 U9 K( S5.39.217.761O4=10 =1+2+3+4=10tvb now,tvbnow,bttvb1 {# `/ b. _5 e- P
2O6= 20 =2+3+4+5+6=20
- n; D9 ~7 N* H$ w4 ?5 D3O5=12 =3+4+5=12
+ _% \' n& o9 t3 t$ C. c" S" Itvb now,tvbnow,bttvb4O8=30 =4+5+6+7+8=305.39.217.762 S3 J4 l* |$ r( e8 I
5O10=? =5+6+7+8+9+10=45 |