Rob2233 发表于 2017-2-23 21:45- U2 T* c- Z1 O: Y4 x5 k6 g9 w V
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, + d' w' w m3 c0 {# s- {这应该是比 ...
S: s. @, l' n, y( | dthanks 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.