Learn Polish: Chociaż padało, dziesięciu obywateli dzisiaj głosowało. - Although it was raining, ten citizens voted today.

This is the core rule for numbers 5 and above. When a subject includes a number like 5, 10, or 100, the verb acts as if the subject is an abstract quantity, not individual people. In the past tense, this means the verb must take the neuter singular ending -o.

Why do we use dziesięciu here instead of the basic number dziesięć?

Because obywatel (citizen) is a masculine personal noun. In Polish, when you count five or more men (or a mixed group including men), you must use the special masculine personal form of the number, which is dziesięciu.

What case is the word obywateli in?

It is in the genitive plural. Numbers 5 and up force the noun they are counting into the genitive case, so dziesięciu obywateli translates literally to 'ten of citizens.'

Why doesn't padało have a subject pronoun like 'it' in front of it?

Polish weather verbs don't need a dummy subject pronoun like 'it' in English. You simply use the 3rd-person neuter singular form of the verb on its own. Padało completely covers 'it was raining.'