Rob2233 发表于 2017-2-23 21:45, G, Q1 t1 V& x- r; I
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,, M1 y9 e C! Y# H# C6 b1 n* q
这应该是比 ...
. w6 C3 l5 t& F Z0 v S7 m9 Rthanks 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.