Rob2233 发表于 2017-2-23 21:45 ; w$ N" ]; h) o" t j8 j9 w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 e, w* R4 u! u
这应该是比 ...
1 m1 d/ L( |* V1 o, qthanks 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.