# NSDecimalSubtract(_:_:_:_:) Subtracts one decimal value from another. ``` func NSDecimalSubtract(_ result: UnsafeMutablePointer, _ leftOperand: UnsafePointer, _ rightOperand: UnsafePointer, _ roundingMode: NSDecimalNumber.RoundingMode) -> NSDecimalNumber.CalculationError ``` ## Discussion Subtracts `rightOperand` from `leftOperand` and stores the difference, possibly rounded off according to `roundingMode`, in `result`. For explanations of the possible return values and rounding modes, see [`NSDecimalAdd(_:_:_:_:)`](/documentation/Foundation/NSDecimalAdd(_:_:_:_:)). For more information, see [Number and Value Programming Topics](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/NumbersandValues/NumbersandValues.html#//apple_ref/doc/uid/10000038i). --- 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)