Rob2233 发表于 2017-2-23 21:45; |, K( q" w8 t
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& c6 g4 L2 H) U, o
这应该是比 ...
8 L! K# [- j$ |$ k# Ythanks 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.