Rob2233 发表于 2017-2-23 21:45+ c' [0 ?- s- J) v" q
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, 1 Z6 x& F4 p0 n! X/ e. Y8 h这应该是比 ...
! c! d) Z+ |$ Y4 S; F3 hthanks 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.