# NSDecimalNormalize(_:_:_:) Normalizes the internal format of two decimal numbers to simplify later operations. ``` func NSDecimalNormalize(_ number1: UnsafeMutablePointer, _ number2: UnsafeMutablePointer, _ roundingMode: NSDecimalNumber.RoundingMode) -> NSDecimalNumber.CalculationError ``` ## Discussion [`Decimal`](/documentation/Foundation/Decimal) instances are represented in memory as a mantissa and an exponent, expressing the value mantissa x 10^exponent. A number can have many representations; for example, the following table lists several valid representations for the number 100: |Mantissa|Exponent| |--------|--------| |100 |0 | |10 |1 | |1 |2 | Format `number1` and `number2` so that they have equal exponents. This format makes addition and subtraction very convenient. Both [`NSDecimalAdd(_:_:_:_:)`](/documentation/Foundation/NSDecimalAdd(_:_:_:_:)) and [`NSDecimalSubtract(_:_:_:_:)`](/documentation/Foundation/NSDecimalSubtract(_:_:_:_:)) call [`NSDecimalNormalize(_:_:_:)`](/documentation/Foundation/NSDecimalNormalize(_:_:_:)). You may want to use it if you write more complicated addition or subtraction routines. For explanations of the possible return values, 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)