Rob2233 发表于 2017-2-23 21:45- F; D. Z, v X1 t
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,6 w$ }/ k5 Q0 s* Y
这应该是比 ...
# X7 {+ b4 J, s( E+ K( \! Pthanks 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.