If this is 184. The english would be 'one hundred and eighty four', if this is 100 80 4, then yes it would be as each number described.
And the only thing by which you can tell that it's 184 and not 100, 80, 4 is the lack of commas.
The app didn't provide 'and' as an option in providing an answer, if written out in English there needs to be an 'and'
There certainly does not need to be an 'and'. This is one hundred eighty four. It could ALSO be one hundred 'and' eighty four, but it by no means NEEDS to be.
For those who are interested (not everyone, I accept) in British English, the 'and' is required, so this allows only a non-British answer currently.
Not in the version where you are given a limited set of words and there is no 'and'.
In that exercise, Duolingo accepts all of the correct responses, including the one phrased in American English.
When you're asked to type an answer freehand, it does indeed accept the International English version, as Jellei has said.
The main answer is "one hundred eighty-four" which I believe is American usage.
I've seen a lot of people writing Poles writing number into one word, for example, they would write "dziewięćdziesiątdziewięć" instead of "dziewięćdziesiąt dziewięć". Do they do this on purpose just to make long polish words?
Well, for normal numerals it's not okay. But you can encounter it with some adjectives for example. „Dziewięćdziesiątdziewięć” is not okay, but „dziewięćdziesięciodziewięciometrowy” is a valid word.