Rob2233 发表于 2017-2-23 21:45 # C& h1 X: B* e1 i7 G2 O. N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, + ?9 N3 }# t6 K- e. Z这应该是比 ...
$ u/ x! _9 n) H/ B& g+ U2 ?thanks 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.