Hvis jeg ser en fejl i teksten, retter jeg den med det samme.

Because Danish main clauses normally follow the V2 rule: the finite verb comes in the second position.

In this sentence, Hvis jeg ser en fejl i teksten is placed first as a whole clause. After that, the main clause starts, and its finite verb must come before the subject:

• Hvis jeg ser en fejl i teksten, retter jeg den med det samme.

So the order is:

• first element: Hvis jeg ser en fejl i teksten
• second element: retter
• then subject: jeg

This is very common in Danish whenever something other than the subject comes first.

Yes. Hvis is the normal word for if in conditional sentences.

So:

• Hvis jeg ser en fejl ... = If I see a mistake ...

A learner may also meet om, which can sometimes translate as if, but usually in the sense of whether:

• Jeg ved ikke, om det er rigtigt. = I don’t know whether it is correct.

So in your sentence, hvis is the correct choice because it introduces a condition.

Yes. Both are present tense:

• ser = see / am seeing
• retter = correct / corrects / am correcting

In Danish, the present tense is usually formed by adding -r to the infinitive:

• at se → ser
• at rette → retter

In this sentence, the present tense gives a general/habitual meaning:

• If I see a mistake in the text, I correct it right away.

It is not necessarily about one specific moment only; it can describe what you normally do.

En is the indefinite article, like a/an in English.

• en fejl = a mistake

It also tells you that fejl is a common-gender noun in Danish. Danish nouns are usually either:

• en-words (common gender)
• et-words (neuter)

Since fejl is an en-word, that matters later when you replace it with a pronoun:

• en fejl → den

Teksten is the definite form of tekst, meaning the text.

Danish usually makes nouns definite by adding the article to the end of the noun:

• en tekst = a text
• teksten = the text

So:

• i teksten = in the text

This is one of the most important features of Danish nouns: the definite article is often a suffix, not a separate word like the in English.

Because den refers back to en fejl, and fejl is a common-gender noun.

So:

• en fejl → den

If the noun were a neuter noun (et-word), you would usually use det instead.

Compare:

• Jeg ser en fejl. Jeg retter den.
• Jeg ser et problem. Jeg løser det.

Here, den means it.

They do two different jobs.

• den refers to fejl:
  
  • retter jeg den = I correct it
• det is part of the fixed expression med det samme, which means immediately / right away

So the two words are not referring to the same thing.

You can think of it like this:

• den = a pronoun with a clear noun reference
• det in med det samme = part of an idiom

It means immediately, right away, or at once.

Literally, it looks like:

• med = with
• det samme = the same

But as a whole, it is an idiomatic expression:

• med det samme = right away

Examples:

• Kom her med det samme! = Come here at once!
• Jeg gør det med det samme. = I’ll do it right away.

So in your sentence:

• retter jeg den med det samme = I correct it immediately

Because Danish commonly uses i for something located in a text, document, book, etc.

So:

• en fejl i teksten = a mistake in the text

This matches English quite closely here. Danish prepositions do not always line up neatly with English, but in this case i is the natural choice.

Yes, you could.

• Hvis jeg ser en fejl i teksten, retter jeg den med det samme.
• Hvis jeg ser en fejl i teksten, så retter jeg den med det samme.

The så can make the connection feel a bit more explicit, like then in English. But it is often omitted, and your original sentence is completely natural.

So:

• without så = very normal
• with så = also normal

Grammatically, it is in the present tense, but the meaning is usually general/habitual.

It means something like:

• Whenever I see a mistake in the text, I correct it immediately.

Danish, like English, often uses the present tense in conditionals of this kind to describe what normally happens.

So the sentence is less about one exact moment and more about a general rule or habit.

It has two parts:

1. a subordinate if-clause
   • Hvis jeg ser en fejl i teksten
2. a main clause
   • retter jeg den med det samme

Word-for-word structure:

• Hvis = if
• jeg = I
• ser = see
• en fejl = a mistake
• i teksten = in the text
• retter = correct
• jeg = I
• den = it
• med det samme = right away

So the sentence is a very good example of:

• a conditional clause first
• then Danish main-clause word order with the verb before the subject

Yes, in standard written Danish, a comma is normally used to separate the if-clause from the main clause:

• Hvis jeg ser en fejl i teksten, retter jeg den med det samme.

So the comma helps show where the subordinate clause ends and the main clause begins. It is especially useful here because the word order changes right after it.