vs
QUICK ANSWER
"Un" is an indefinite article which is often translated as "a", and "cuarenta" is an adjective which is often translated as "forty". Learn more about the difference between "un" and "cuarenta" below.
un(
oon
)An indefinite article is a word that indicates that a noun is not specific (e.g., a girl).
1. (singular)
b. an (before vowel sound)
Tienen una vieja cámara que todavía funciona.They have an old camera which is still working.
cuarenta(
kwah
-
rehn
-
tah
)A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).