Rob2233 发表于 2017-2-23 21:45 & F$ y% o/ j0 F% [# r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, ) M3 x: ~2 `$ z# i t. g- l这应该是比 ...
7 V3 |5 d9 H, l& B2 gthanks 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.