Rob2233 发表于 2017-2-23 21:45 - d3 y. C. _& P( }; J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- ]$ ^3 S: W0 l2 @* ?这应该是比 ...
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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.