Rob2233 发表于 2017-2-23 21:45 ! p c* ~5 }/ {3 q: U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,* F+ \0 O. e5 ^" ?2 F9 X: w8 G
这应该是比 ...
# o( M, R* q, D! R5 U2 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.