Rob2233 发表于 2017-2-23 21:45( |7 h3 f- o: ?
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,3 ^8 b2 \, Y& Z. g
这应该是比 ...
* ]* k$ n7 K+ q. X1 d
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.