It's the plural of "um", indefinite masculine article.
The plural of the indefinite article expresses a non-exact quantity.
So, "He is some thirty years old" should be correct, but was not accepted.
If Duo accepted that, would they automatically incorporate that answer into the reverse PT > Eng version too? Whilst I would say your answer isn't incorrect, it is somewhat archaic and would never recommend someone learning English to learn that usage, even as an 'alternative answer'.
Instead of just saying 'No', could you explain? I have always heard the words 'some' or 'around' when discussing age much more often than 'about' or 'like'. I would correct anyone who used 'like' but 'some' is used in English at least since Shakespeare.
I don't like the solution using the word 'like' as a replacement for about. While it is common slang. It should only be used in speech. I don't think Duo should be teaching it as a written or acceptable alternative to almost. Especially as English speaking school systems (personal experience teaching in the USA and UK) teach that it as an unacceptable contextual use of the word "like".
100% they should accept "he has some thirty years old"... I am a native English speaker and this is used every day in our language.
"Uns" in this sentences would mean "some,around,about". It shows the person is not sure about the age of another person. This is the why the answer included"about"
He is around thirty years old was marked incorrect, but this would be said in english...
One natural American English translation of this would be "He's thirty-something".
Is it really necessary to include ¨old¨ at the end of the sentence? It is so common place in England to omit this.
In both AmE and BrE, there is a preference for "He is thirty" over "He is thirty years old". It would be unusual in AmE to say He is thirty years.