"The merchant has many gold pieces."

Translation: Mercator multos aureos habet.

[lflonghi]

Can someone decline Aureos, please?

[CaueCanem]

Here is the full declension of the word "Aureus".

Masculine:
Aureus - Nominative / Subject;
Aurei - Genitive / Possesive;
Aureo - Dative / Indirect Object;
Aureo - Ablative;
Aureum - Accusative / Direct Object;

Feminine:
Aurea - Nominative / Subject;
Aureae - Genitive / Possesive;
Aureae - Dative / Indirect Object;
Aurea - Ablative;
Auream - Accusative / Direct Object;

Neuter:
Aureum - Nominative / Subject;
Aurei - Genitive / Possesive;
Aureo - Dative / Indirect Object;
Aureo - Ablative;
Aureum - Accusative / Direct Object;

Hope that was helpful.

[RickBradleyUSA]

Just made the connection that aureus isn't just an adjective for gold, but was also a coin
aureus m (genitive aureī); second declension
(numismatics) gold coin equivalent to 25 denarii, aureus (up to the 4th century AD)
https://en.wiktionary.org/wiki/aureus#Latin

[Moopish]

You can find all forms at: https://en.wiktionary.org/wiki/aureus#Latin

Just go to the section for the noun use of aureus or follow the masculine forms for the adjective use.