Learn Spanish (Spain): El piso tiene siete ventanas. - The apartment has seven windows.

No. Unlike the number one (un or una), the numbers two through ten do not change their ending to match the gender of the word they describe. You just use siete for both masculine and feminine things.

Doesn't piso usually mean floor?

Yes, piso can mean floor, like the ground or a level of a building. However, in Spain, it is also the most common word for apartment or flat. In Latin America, you are more likely to hear apartamento or departamento instead.

What verb does tiene come from?

It comes from the common verb tener (to have). Because el piso is a singular thing (it), we use the third-person singular form tiene.

How do I pronounce the vowels in siete?

The i and the e blend together into a single sound, similar to the start of the English word yelling. It is pronounced smoothly as syeh-teh, rather than separating it into see-eh-teh.