Could it also be "Children have a cookie"?
( The hover over listed 3 different meanings).
No, ciasteczko is a cookie (nominative and accusative singular). Ciazteczka is cookies (nominative and accusative plural).
The reason that ciasteczka also has cookie listed as a hint is because it's also the genitive singular form, meaning (of a) cookie. But the verb to have is followed by the accusative, not genitive case.
I'm kind of confused with the polish meanings of the word 'have'. Is it maja or mam or mamy. I understand when you should use mam and mamy but not maja. When do you use maja?
All of them are forms of "to have".
"mam" is 1st person singular, "mamy" is 1st person plural, "mają" is 3rd person plural.
There's also: "masz" (2nd person singular), "macie" (2nd person plural) and "ma" (3rd person singular).
Yeah, I answered that question a year ago. How did you see the question but not my answer? o.O
It's accusative. Mam (I have) + acc.; Nie mam (I don't have) + gen; Instrumental form is used after some prepositions, when one wants to say: I did it with a tool - name of that tool would be in instrumental or when one wants to say A is B, if B is a function, object (when B is a proper name we use nominative).