Questions & Answers about Tämä on huone kymmenen.
Why is it huone kymmenen instead of kymmenen huonetta?
When a number comes after a noun to act as a label or name (like "room ten"), both words stay in their basic dictionary form. If you want to count the rooms and say "ten rooms", the number comes first and forces the noun into the partitive case: kymmenen huonetta.
Is kymmenen always spelled with a double 'm'?
Yes! It is a very common mistake for English speakers to write it with just one 'm', but kymmenen has two. When speaking, make sure to hold that 'm' sound a little longer.
Why do we use tämä here instead of se?
Tämä means "this", and you use it when you are physically close to the room you are pointing out. If you were just talking about the room in a general conversation without pointing to it, you would usually use se ("it").
If I want to say "in room ten", do both words change their endings?
No, only the noun changes! You would say huoneessa kymmenen. Because the number is just acting as a name tag for the room, kymmenen stays in its basic form, while huone gets the "in" ending.