This is the 764th most frequent Icelandic word.
nemendum
"Nemendum" means "students" in English (dative plural form).
The word 'nemendum' is the dative plural form of 'nemandi' (student) and is used here as the indirect object receiving the action of the verb 'útskýrði'.
Kennarinn útskýrði verkefnið fyrir nemendum í bekknum.
The teacher explained the assignment to the students in the class.
In this sentence, 'nemendum' again appears in its dative plural form, serving as the entity to whom the 'rules' (subject) were 'introduced'.
Reglurnar voru kynntar nemendum áður en kennslan hófst.
The rules were introduced to the students before the lesson began.
Here, 'nemendum' is used in the dative plural to indicate the audience or beneficiaries of the 'teachers' being 'role models'.