what is the different : mein,meine,meinen
Gender and grammar case. http://en.wiktionary.org/wiki/mein#Inflection
And this table is the reason why everyone despises German articles.
So, when eating rice, we speak of it in plural? Because I was failed for "meinem Reis".
Well when eating something, the subject should be in the accusative case not the dative case. If I'm thanking the rice or something it might be meinem rice (but I'm not too sure, we haven't learned dative pronouns yet).