Rob2233 发表于 2017-2-23 21:45$ j0 w, E' p% Z
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 L* g( d# W+ H2 s2 D* c7 D
这应该是比 ...
8 K' E/ r* M; H4 o6 A6 H1 B% Dthanks 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.