Rob2233 发表于 2017-2-23 21:45. n' H7 `% [9 n" F; e, s
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,% A6 ^# ]/ c- G5 P! ^
这应该是比 ...
/ v5 c% y& U& I2 s4 b7 A, t; qthanks 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.