Rob2233 发表于 2017-2-23 21:455 w3 B5 r( y/ ~, C( \7 |- d/ x( 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, 8 h) N7 F( R W这应该是比 ...
" A9 G1 f4 w4 U: Gthanks 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.