Rob2233 发表于 2017-2-23 21:45" }5 r. z( g* E3 D6 i$ 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, 1 @9 y3 I) ]" o7 p这应该是比 ...
, w& A; V- r% V# Athanks 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.