Rob2233 发表于 2017-2-23 21:45/ p- [; e9 k% r
如果觉得难度不够的话,可以试试加拿大公开赛(Canadian Open Mathematics Challenge)的题,5 x0 ?) g5 T( m6 ]# d* z. c
这应该是比 ...
. N# k6 w# Z% g o6 g+ I1 p ethanks a lot as parents, but i guess my daughter going to hate you. i won't let her know who you are. please keep sending this kind good resource for all parents.