Rob2233 发表于 2017-2-23 21:45: b3 _0 C+ |6 e. C Y
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, 8 ?3 U5 r+ n7 L' Z H# q* [这应该是比 ...
9 ]. f" ]/ I- U% Q8 ^thanks 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.