Rob2233 发表于 2017-2-23 21:45; v* r% | y! p* X, t3 d# M
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, ! s3 Q8 a0 z- a# B这应该是比 ...
0 Y6 z$ Y) M, q& \- 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.