The word our is a possessive pronoun that gets used as an adjective. It modifies a noun.
That is our dog.
We live in our house.
The word ours is a possessive pronoun that takes the place of a noun.
The dog is ours.
The house is ours.
Both our and ours show possession. Use the word our as an adjective to modify a noun. Use the word ours as a pronoun taking the place of a noun.
▶It’s your turn. Decide if you should use our or ours in this blank: The red car is ____. Did you choose the word that is a possessive pronoun? Good for you!