Rob2233 发表于 2017-2-23 21:459 c: E, H# Y6 a' [* @
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,( K8 m. v/ P4 i& B' n5 L6 C \; G
这应该是比 ...
! x5 N/ q9 H) @4 B& [6 O/ |# tthanks 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.