Learn Hardcore Norwegian: Vi går inn i stuen én om gangen. - We go into the living room one at a time.

inn i stuen: emphasizes movement into the living room from outside.
- Vi går inn i stuen = We go into the living room (we were outside it).
i stuen alone: describes being in or moving within the living room.
- Vi er i stuen = We are in the living room.
- Vi går i stuen = We walk around in the living room.

So inn i expresses entering, while i by itself expresses being located in (or moving inside).

Why is it stuen and not stue? Where is the word “the”?

Norwegian usually marks definiteness with an ending on the noun, not a separate word like English the.

stue = a living room (indefinite)
stuen = the living room (definite)

The -en ending corresponds to English “the” for masculine/feminine nouns in Bokmål.

So i stuen literally is “in living-room-the” → in the living room.

Are stuen and stua the same thing? When do you use which?

Yes, they mean the same: “the living room.”

They are just two accepted Bokmål forms of the definite:

stuen = more “traditional”/bookish Bokmål
stua = more colloquial / everyday speech for many people

Both are correct in written Bokmål; choice depends on style and dialect preference. In this sentence you could also write:

Vi går inn i stua én om gangen.

with the same meaning.

Why is there an accent in én? What’s the difference between en and én?

Both are related to “one”, but:

en = indefinite article (a / an), and also the number one.
én (with accent) = clearly the number “one”.

The accent is used to avoid ambiguity and to stress that you really mean the number, not just a/an.

In én om gangen, you want to emphasize “one (person) at a time,” so én is written with an accent.

Do Norwegians always write the accent in én, or can they just write en?

They can just write en, and in everyday writing many people do.

However, the accent is:

recommended when you need to clearly show it’s the number:
- Jeg har bare én sønn. = I have only one son.
less crucial when context is obvious.

In én om gangen, you will very often see the accent, because this is a fixed, very common phrase meaning “one at a time.”

What does om gangen literally mean, and can I use it with other numbers?

Literally:

om can mean per / at a time / each in some expressions.
gangen comes from gang = time, occurrence (here in the definite form: the time).

So om gangen is like “per time / at a time.”
én om gangen = one at a time.

Yes, you can use it with other numbers:

to om gangen = two at a time
tre om gangen = three at a time
en bok om gangen = one book at a time

Can I move én om gangen to another place in the sentence?

Yes, Norwegian word order is fairly flexible for adverbial phrases like this, though the version you have is very natural:

Vi går inn i stuen én om gangen. (neutral, very natural)

Other possible orders:

Vi går én om gangen inn i stuen. (slightly more focus on one at a time)
Én om gangen går vi inn i stuen. (strong emphasis on the one-at-a-time rule)

All are grammatically correct; changes in order mainly affect emphasis and style, not basic meaning.

Could I use another verb instead of går, like kommer or drar? What would change?

Yes, but each verb has its nuance:

går = go / walk
- Neutral, very common for physically moving by foot:
  - Vi går inn i stuen. = We go/walk into the living room.
kommer = come (movement towards the speaker or a reference point)
- Vi kommer inn i stuen. = We come into the living room (from the perspective of someone already there or expecting us).
drar = go / leave / head off (often for longer distances, not usually just entering a room)
- Vi drar inn i stuen sounds odd; drar is more for going to another place, not just stepping into a room next door.

In this context, går (or kommer, depending on perspective) is the natural choice; drar is not.

Does Vi går inn i stuen mean “We walk into the living room” or “We are going into the living room”? How is the present tense used?

Norwegian present tense (går) can cover several English uses:

General or repeated action
- Vi går ofte inn i stuen. = We often go into the living room.
Right-now action
- Vi går inn i stuen nå. = We are going into the living room now.
Near future, planned (with time marker)
- Vi går inn i stuen om et øyeblikk. = We’re going into the living room in a moment.

So Vi går inn i stuen can be translated as:

We go into the living room
or We are going into the living room,

depending on context. Norwegian doesn’t distinguish these with a different verb form.

Why is it i stuen and not til stuen? What’s the difference between i and til here?

Both i and til can involve movement, but they’re used differently:

i = into / in (entering and ending inside a place)
- Vi går inn i stuen. = We go into the living room (we end up inside it).
til = to / up to (movement towards a place, not necessarily inside)
- Vi går bort til stuen. = We walk over to the living room (to the door/area near it).

If you say inn til stuen, it usually means in towards the living room, often up to it, not clearly into it. To express clearly going into the room, inn i stuen is the standard choice.

Is Vi går inn i stuen én om gangen formal or informal, and is it Bokmål or Nynorsk?

It is written in Bokmål.
The style is neutral: fine in both spoken and written Norwegian.
You could make it slightly more informal by using stua instead of stuen:
- Vi går inn i stua én om gangen.

Both versions are perfectly normal; the original sentence is standard, neutral Bokmål.