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dataframe/docs/StardustDocs/topics/concepts/nanAndNa.md

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+[//]: # (title: NaN and NA)
+
+Using the Kotlin DataFrame library, you might come across the terms `NaN` and `NA`. 
+This page explains what they mean and how to work with them.
+
+## NaN
+
+`Float` or `Double` values can be represented as `NaN`,
+in cases where a mathematical operation is undefined, such as for dividing by zero. The
+result of such an operation can only be described as "**N**ot **a** **N**umber".
+
+This is different from `null`, which means that a value is missing and, in Kotlin, can only occur
+for `Float?` and `Double?` types.
+
+You can use [fillNaNs](fill.md#fillnans) to replace `NaNs` in certain columns with a given value or expression
+or [dropNaNs](drop.md#dropnans) to drop rows with `NaNs` in them.
+
+## NA
+
+`NA` in Dataframe can be seen as: [`NaN`](#nan) or `null`. Which is another way to say that the value
+is "**N**ot **A**vailable".
+
+You can use [fillNA](fill.md#fillna) to replace `NAs` in certain columns with a given value or expression
+or [dropNA](drop.md#dropna) to drop rows with `NAs` in them.