Rob2233 发表于 2017-2-23 21:45 * V% S P( N. d# L6 Z" v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,2 ]5 f z3 m, V3 L/ h$ u+ H) ~
这应该是比 ...
, Z3 j- ]; O* B- l( Hthanks 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.