Declension table of ?kartra

Neuter	Singular	Dual	Plural
Nominative	kartram	kartre	kartrāṇi
Vocative	kartra	kartre	kartrāṇi
Accusative	kartram	kartre	kartrāṇi
Instrumental	kartreṇa	kartrābhyām	kartraiḥ
Dative	kartrāya	kartrābhyām	kartrebhyaḥ
Ablative	kartrāt	kartrābhyām	kartrebhyaḥ
Genitive	kartrasya	kartrayoḥ	kartrāṇām
Locative	kartre	kartrayoḥ	kartreṣu

Compound kartra -

Adverb -kartram -kartrāt