Rob2233 发表于 2017-2-23 21:45 # d9 S L( G* F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, . f( o6 p! c+ e, B这应该是比 ...
7 w, p8 [5 D2 I! v$ J, N& fthanks 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.