Translation:Seven secretaries work with the judge.
Wouldn’t the singular form of the noun be used with this number, viz seachtar rúnaí rather than seachtar rúnaithe?
It actually looks like it gets put into the genitive plural. Which is why you have tríúr ban.
Ah, that makes sense, thank you. My Irish grammar book stated that the singular form of the noun should be used, but listed ban as an exception; it would have been clearer if it had stated that the genitive plural form should be used.
Note, I'm not 100% sure, but that's what it looks like (note: triúr fear, where fear is genitive plural of, well, fear). It's the only thing I can think of to make sense.
As stated above, the genitive plural is traditionally used but that the nominative singular can be used with exceptions.
Addendum: from p168 of the standard (available here: http://www.oireachtas.ie/parliament/media/Final-Version.pdf) is é an ginideach iolra den ainmfhocal a leanann an uimhir phearsanta. So, genitive plurals only in the course, please, but who knows what you may encounter in the wild.
The numbers for counting people (beirt go deichniúr) are all nouns. They take the Ginideach Iolra after them. Beirt is also feminine so you add a seimhiú onto the next noun. You'll need to know the tréaniolra and lagiolra for these.
Beirt- Beirt fhear, Beirt mhúinteoirí.
Triúr- Triúr fear, Triúr múinteoirí.
Ceathrar- Ceathrar fear, Ceathrar múinteoirí.
The joys of the Tuiseal Ginideach, Hollywood will have to make a horror film out of it.