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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 638b66d2-9f06-4f60-8781-808709e1485c

microsoft/knowledge/data-modeling/round-direction-symbols-use-magnitude.md

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+---
+bc-version: [all]
+domain: data-modeling
+keywords: [round, rounding, direction, precision, negative-decimal, amount]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# `Round` direction symbols follow magnitude, not mathematical ordering
+
+## Description
+
+AL's `Round(Number, Precision, Direction)` uses `'>'` to round away from zero and `'<'` to round toward zero. For a negative value this reverses mathematical ordering: `Round(-1234.56789, 0.001, '<')` returns `-1234.567`, while direction `'>'` returns `-1234.568`. Code that treats the symbols as mathematical ceiling and floor produces sign-dependent amount errors, commonly on credit documents and negative adjustments.
+
+## Best Practice
+
+Choose the direction from the business meaning: `'>'` increases absolute magnitude and `'<'` decreases absolute magnitude for both positive and negative values. Include positive and negative cases whenever a directed rounding rule is tested.
+
+See sample: `round-direction-symbols-use-magnitude.good.al`.
+
+## Anti Pattern
+
+Using `'<'` as a mathematical floor or `'>'` as a mathematical ceiling. The result looks correct for positive amounts but moves in the opposite mathematical direction for negative amounts.
+
+See sample: `round-direction-symbols-use-magnitude.bad.al`.
+
+## Reference
+
+[Use the Round function](https://learn.microsoft.com/en-us/training/modules/use-document-standards-business-central/4a-use-round-function)