Breakdown of My mamy trzy, a oni cztery.
mieć
to have
oni
they (masculine personal)
my
we
a
and / whereas (contrast)
Questions & Answers about My mamy trzy, a oni cztery.
Why use a for 'and' instead of i?
In Polish, i is used to simply add things together. The word a is used to show a contrast or comparison between two things, similar to 'while' or 'whereas' in English. Since we are contrasting what 'we' have versus what 'they' have, a is the correct choice here.
I thought we usually drop pronouns like my. Why is it included here?
You are right that Polish usually drops pronouns because the verb ending (like the -my in mamy) already tells us who is doing the action. However, when we want to emphasize or contrast who is doing what (WE have three, but THEY have four), we keep the pronouns my and oni to make that contrast clear.
Where is the verb for 'they have' in the second half of the sentence?
If the verb is the same in both halves of a comparison, you can skip it to avoid repeating yourself. Instead of saying a oni mają cztery (and they have four), it is very natural in Polish to just say a oni cztery (and they four).
Are trzy and cztery the basic dictionary forms of these numbers?
Yes! trzy (three) and cztery (four) are the standard forms you use when counting objects or stating a standalone number. Because we do not mention any specific objects here that might change the word ending, we just use these basic counting forms.