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# NFT Rarity Calculation

There are 4 known rarity calculation methods:

* Trait Rarity Ranking
* Average Trait Rarity
* Statistical Rarity
* Rarity Score

We are using the Rarity Score method, which is used by `rarity.tools`.

In this method an attribute’s rarity score is calculated by this formula:

`11 / ([Number of Items with that Trait Value] / [Total Number of Items in Collection])`

So, we are calculating all attribute rarity scores with this method and sum all of them to find the item rarity scores.