This is the 12153rd most frequent Polish word.
mandarynki
Mandarynki: tangerines.
In this sentence, 'mandarynki' is used in the nominative plural form to indicate the subject of the sentence, referring to 'mandarins' as a type of fruit.
Mandarynki są moim ulubionym owocem.
Mandarins are my favorite fruit.
Here, 'mandarynek' is in the genitive plural form because it follows 'kilka,' which is a quantifier requiring the genitive case in Polish.
Mam ochotę na kilka mandarynek.
I feel like having a few mandarins.
In this occurrence, 'mandarynki' is in the accusative plural form, used as the direct object of the verb 'kupiliśmy,' meaning 'we bought.'