Learn Polish: Ten tekst ma tysiąc słów. - This text has a thousand words.

This is the main rule for numbers 5 and above! After numbers like pięć (five), sto (a hundred), or tysiąc (a thousand), the noun that follows must be in the Genitive plural case. So we use the Genitive plural słów instead of the regular Nominative plural słowa.

How do we get słów from the basic word słowo?

To form the Genitive plural for most neuter nouns ending in -o, you drop that final letter. If you drop the -o from słowo, you get "słow". However, Polish often changes a regular o to an ó (which sounds like "oo") when it is the last vowel before a consonant at the end of a word, resulting in słów.

Wait, shouldn't the object of ma (has) be in the Accusative case?

Yes, it is! The verb mieć (to have) takes the Accusative case. Here, the direct object is actually the number tysiąc. Because tysiąc behaves like a masculine inanimate noun, its Accusative form looks exactly the same as its basic Nominative form.

Why is it ten tekst and not to tekst?

Even though tekst refers to a thing, it is grammatically a masculine noun in Polish. Therefore, it needs the masculine word for "this", which is ten. The word to is only used for neuter nouns.