Rob2233 发表于 2017-2-23 21:451 e: {" ^, n! J" R% P2 X6 E
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,$ D: D8 J; w+ H
这应该是比 ...
2 z6 |* x8 V8 R7 N1 y3 v0 Lthanks 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.