Rob2233 发表于 2017-2-23 21:45# Y% G7 r: E7 J; y# D s& h
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, Y- _9 Q" W( f) g
这应该是比 ...
0 v5 w1 B- V/ c9 S+ W7 \6 l. \( p+ W
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.