# SignedNumeric A numeric type with a negation operation. ``` protocol SignedNumeric : Numeric ``` ## Overview The `SignedNumeric` protocol extends the operations defined by the `Numeric` protocol to include a value’s additive inverse. # Conforming to the SignedNumeric Protocol Because the `SignedNumeric` protocol provides default implementations of both of its required methods, you don’t need to do anything beyond declaring conformance to the protocol and ensuring that the values of your type support negation. To customize your type’s implementation, provide your own mutating `negate()` method. When the additive inverse of a value is unrepresentable in a conforming type, the operation should either trap or return an exceptional value. For example, using the negation operator (prefix `-`) with `Int.min` results in a runtime error. ``` let x = Int.min let y = -x // Overflow error ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)