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# notANumber

A decimal number that specifies no number.

```
@NSCopying class var notANumber: NSDecimalNumber { get }
```

## Return Value

An `NSDecimalNumber` object that specifies no number.

## Discussion

Any arithmetic method receiving [`notANumber`](/documentation/Foundation/NSDecimalNumber/notANumber) as an argument returns [`notANumber`](/documentation/Foundation/NSDecimalNumber/notANumber).

This value can be a useful way of handling non-numeric data in an input file. This method can also be a useful response to calculation errors. For more information on calculation errors, see the [`exceptionDuringOperation(_:error:leftOperand:rightOperand:)`](/documentation/Foundation/NSDecimalNumberBehaviors/exceptionDuringOperation(_:error:leftOperand:rightOperand:)) method description in the [`NSDecimalNumberBehaviors`](/documentation/Foundation/NSDecimalNumberBehaviors) protocol specification.

---

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