Nouns in -us and -um are declined as follows:--

Hortus, _garden_; Bellum, _war_;
stem, hortŏ-. stem, bellŏ-.
SINGULAR.
TERMINATION. TERMINATION.
_Nom._ hortus -us bellum -um
_Gen._ hortī -ī bellī -ī
_Dat._ hortō -ō bellō -ō
_Acc._ hortum -um bellum -um
_Voc._ horte -e bellum -um
_Abl._ hortō -ō bellō -ō

PLURAL.
_Nom._ hortī -ī bella -a
_Gen._ hortōrum -ōrum bellōrum -ōrum
_Dat._ hortīs -īs bellīs -īs
_Acc._ hortōs -ōs bella -a
_Voc._ hortī -ī bella -a
_Abl._ hortīs -īs bellīs -īs

Nouns in -er and -ir are declined as follows:--

Puer, _boy_; Ager, _field_; Vir, _man_;
stem, puerŏ- stem, agrŏ- stem, virŏ-
SINGULAR. TERMINATION.
_Nom._ puer ager vir Wanting
_Gen._ puerī agrī virī -ī
_Dat._ puerō agrō virō -ō