For questions about how and in what order Mathematica evaluates expressions, tracing evaluation (Trace family), handling expressions in unevaluated form (Hold, HoldForm, HoldPattern, Unevaluated, Defer), nonstandard or controlled evaluation (ReleaseHold, Evaluate), etc.

Questions about algebraic simplification of expressions should use . Questions about structural replacement/manipulation in/of held expressions should use .

Useful links

Example questions

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