How about "He is a year old"?
Would it not be "He has a year"?
Romance languages tend to use the verb to have when talking about age. Italian is the same. He has one year would be the literal translation, however it is not really what the sentence means
he's one year or he is one year for me it is the same
I thought the same thing
It should be correct to say, "he is a year old", or "he is one year old."
Agreed - but 'a year' is still marked wrong