Rob2233 发表于 2017-2-23 21:453 Y. s7 @* \' F' h# l
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,- Z. C1 C' F8 E( @, u J/ U% F
这应该是比 ...
0 m/ a8 J. h4 w Ethanks 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.