Min billet gælder også i metroen.

Because billet is a common-gender noun in Danish: en billet.

In Danish, possessive words agree with the noun’s gender:

• min
  • common gender singular
• mit
  • neuter singular
• mine
  • plural

So:

• min billet = my ticket
• mit hus = my house
• mine billetter = my tickets

That is normal in Danish when you use a possessive like min.

Just like in English, you do not say my the ticket. Danish works the same way:

• min billet = my ticket
• not min billetten
• not min en billet

The possessive already makes the noun phrase definite enough.

Gælde means something like:

• to be valid
• to apply
• to count

In this sentence, Min billet gælder også i metroen, it means:

• My ticket is also valid on/in the metro

This verb is very commonly used for tickets, rules, offers, prices, and agreements:

• Billetten gælder i 24 timer = The ticket is valid for 24 hours
• Reglen gælder for alle = The rule applies to everyone

This is normal Danish word order.

In a main clause, the verb usually comes early, and adverbs like også often come after the finite verb:

• Min billet gælder også i metroen

That placement is very natural. Compare:

• Jeg kommer også = I’m coming too
• Han er også træt = He is also tired

English speakers often want to put also in other places, but Danish has its own usual adverb position.

In this sentence, i metroen is the normal choice.

Here, i means something like in the metro / on the metro system / in the subway. Danish often uses i where English might say on.

So:

• i metroen = in/on the metro
• i bussen = on the bus
• i toget = on the train

English and Danish do not always match preposition-for-preposition, so this is something you often just have to learn as a phrase.

Because metroen is the definite singular form of metro.

Danish usually adds the definite article to the end of the noun:

• en metro = a metro
• metroen = the metro

This is very common in Danish:

• en bil → bilen = the car
• en station → stationen = the station

So i metroen literally means in the metro / in the subway.

Yes. It is normally:

• en metro

So the definite singular is:

• metroen

That is why you see -en and not -et.

Yes, that is possible.

• Min billet gælder også i metroen = My ticket is also valid in the metro
• Min billet er også gyldig i metroen = My ticket is also valid in the metro

Both are understandable and correct. But with tickets, gælde is very idiomatic and extremely common in Danish. It often sounds a bit more natural than være gyldig in everyday transport contexts.

No. Gælde is used in several common ways.

For example:

• Reglen gælder ikke her = The rule does not apply here
• Tilbuddet gælder til fredag = The offer is valid until Friday
• Det gælder mig også = That applies to me too

So the core idea is to be valid / to apply.

A rough guide is:

• gælder ≈ GEL-ur

But the exact Danish sounds are different from English. A few points:

• æ sounds a bit like the vowel in English bed, but not exactly
• the d in gælder is usually soft, not a strong English d
• the ending -er is often reduced in natural speech

So the word may sound smoother and less sharply pronounced than an English speaker expects.

It follows a very common Danish pattern:

• Min billet = subject
• gælder = verb
• også = adverb
• i metroen = prepositional phrase

So:

• Min billet gælder også i metroen

This is a straightforward main clause with standard word order.

Yes, but the emphasis changes, and Danish word order rules still apply.

For example:

• I metroen gælder min billet også.
  = In the metro, my ticket is also valid.

That version puts focus on i metroen.

But you cannot freely move words around in Danish the way learners sometimes try to. Danish main clauses follow the verb-second pattern, so if one element moves to the front, the verb still stays in second position.

Yes, in meaning it often corresponds to both too and also.

In this sentence:

• Min billet gælder også i metroen
  = My ticket is also valid in the metro

Depending on context, English might also say:

• My ticket is valid in the metro too

So også is a very useful everyday word meaning also / too.