Rob2233 发表于 2017-2-23 21:45: k4 \6 {/ n; p4 P. J( b
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, ) r [. b% j. y9 V+ q- e- F这应该是比 ...
, l; ^1 L6 y/ z3 \0 U8 Fthanks 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.