Questions & Answers about Den regel gælder også i skolen.
Because regel is a common-gender noun in Danish. Common-gender nouns take den in the singular, while neuter nouns take det.
- en regel = a rule
- den regel = that rule / the rule (depending on context)
So det regel would be incorrect.
Den regel and reglen are not exactly the same.
- reglen = the rule
- den regel = usually that rule
In Danish, using den + noun often points to a specific noun in a more demonstrative way, like English that. So Den regel gælder også i skolen most naturally feels like That rule also applies in school / at school.
If you said Reglen gælder også i skolen, that would more naturally mean The rule also applies in school.