Rob2233 发表于 2017-2-23 21:45! l' N( ~ i; a9 O
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, : T: ?0 ^. s! l) ~1 W" Y这应该是比 ...
/ A: P5 a$ y8 D) j# T2 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.