A question you ask yourself every day. I have to say, some of the sentences aren't useful, but this one is. Good job Duolingo.
Except that mo chuid eochracha would have been better than m’eochracha, since it’s a possessive adjective governing a plural noun.
Is this the case both for everyday speech and grammar rules, or is the differentiation mostly formal in this case?
Yes, eochracha is the plural of eochair ; not all Irish plurals are formed by appending -í.