Level IV of XX on the frequency path
Frequency rank 426 / 2,608
Frequent enough that you will keep running into it once you read past headlines.
More common than 負 (Lose), less common than 価 (Value).
The character for simple (単) looks like a flat table with a single item on top — just one thing, nothing complicated, keeping it simple.
単 is rank 426 of 2,608 in published Japanese.
Study 単 →