# Help:FAQ/Questions about contributions/Why do we need \left and \right with every pair of parentheses?

## Why do we need \left and \right with every pair of parentheses?
"Do we really need to put \left({ ... }\right) for every parenthesis, even things like $\sin(2x)$ and $(2n)!$? Out of curiosity, what difference does the extra curly inside \left(...\right) make? It seems to display the same."
The curly braces are grouping indications for $\TeX$; they serve to ensure that every \left is paired with the intended \right. Especially when using an external editor (e.g. via the Firefox plug-in It's all text) that highlights matching braces, such can greatly simplify the frustrating search for an occasional omitted or excess brace.
Equation references like $(1)$ and $(3′)$ are excepted from this admittedly strict style rule. --Lord_Farin (talk) 17:57, 13 December 2012 (UTC)
UPDATE: This has now been more or less superseded by the new custom $\LaTeX$ commands which have recently been added. Please consult Symbols:LaTeX Commands/ProofWiki Specific for an idea of the sort of thing we are moving towards, for example: $\map f x$ is now generated using \map f x, and $\tuple {a, b, c}$ by \tuple {a, b, c}, and so on.