Rob2233 发表于 2017-2-23 21:456 @+ e! _- k8 ?, t. |! p0 B' Q
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, ( l; B. @ O9 A# @这应该是比 ...
% d( s9 S9 [& G) u5 b* o$ X" uthanks 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.