Rob2233 发表于 2017-2-23 21:45 5 w7 E) r/ i8 L# ? B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,) N& `. X4 t i, ~
这应该是比 ...
$ v0 B2 G9 A3 ]% o! 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.