Answer:
Unos means 'some' or 'a few' and is masculine.
Unas means 'some' or 'a few' and is feminine.
For example:
Hay unos niños en ese parque = There are some kids in that park
Niños is masculine so you use unos.
Dime unas palabras en inglés = Tell me some words in English
Palabras is feminine so you use unas.
Hope this helps :) It's not very hard once you practise a few times.
