Learn Danish: Selvom løsningen var simpel, fungerede den godt. - Although the solution was simple, it worked well.

Even though løsningen (the solution) is a definite noun, the adjective comes after the verb var (was). This is called a predicative adjective. In Danish, adjectives in this position only change to match plural number or neuter gender; they do not take the definite ending. If you put it directly in front of the noun instead, you would use the definite form and drop the 'e' from the middle: den simple løsning (the simple solution).

Why does the verb fungerede come before the subject den?

This is the classic V2 (verb-second) rule. The entire first part of the sentence (Selvom løsningen var simpel) is a subordinate clause acting as a single block in position one. To ensure the main verb stays in the second position of the full sentence, fungerede must come immediately after the comma, causing it to swap places with its subject den.

Why is "it" translated as den instead of det?

In Danish, you must match the pronoun "it" to the gender of the noun it replaces. Here, it refers back to løsningen (the solution). Because the base word is an en-word (en løsning), you must use den.

Why does godt end with a -t here?