Rob2233 发表于 2017-2-23 21:45 , l: y9 i8 M6 K) m, Q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 e) v: z% i# h: I5 F
这应该是比 ...
# S6 H2 e5 r* ~5 Othanks 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.