Rob2233 发表于 2017-2-23 21:457 k8 n1 [% Q. s/ D# |# 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, ' S3 |! z% M, E5 ~- j5 c6 f/ r: V7 \这应该是比 ...
$ Z: _% W5 f& [' Q. W9 Ithanks 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.