Rob2233 发表于 2017-2-23 21:45 # @/ Q, k; p5 k# u2 e* E5 o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, ' H9 A( n5 e" Q- C这应该是比 ...
1 v' \& k; j* t7 t; x. e" fthanks 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.