Rob2233 发表于 2017-2-23 21:45, B& l; z4 [: Q, C
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, 5 U/ b9 q( _* f+ {6 p1 g& [/ F/ Q这应该是比 ...
0 }6 k7 r7 q" C( t1 ~9 A) W# Kthanks 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.