Rob2233 发表于 2017-2-23 21:45 , z7 U3 J; `4 k! t. U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, % h+ d' L: P/ r* G这应该是比 ...
2 c w) F8 Q3 dthanks 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.