Rob2233 发表于 2017-2-23 21:45( t3 b: Y& V( W: k0 i1 s
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,3 |/ ^1 n4 x: k
这应该是比 ...
- G+ Q" S# ]) c5 lthanks 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.