Rob2233 发表于 2017-2-23 21:45 ! ?' i( w: o, e) R$ \9 j) ?+ i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,. E& ]3 g" P4 ~3 V" F/ s
这应该是比 ...
% d7 P; {* [! x E) Y' k5 Hthanks 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.