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== precision ==

 &#123;{#invoke:math|precision|''n''}}
 &#123;{#invoke:math|precision|x=''n''}}

<syntaxhighlight lang="lua">
mm._precision(number_string)
</syntaxhighlight>

Detemines the precision of a number. For example, for "4" it will return "0", for "4.567" it will return "3", and for "100" it will return "-2".

The function attempts to parse the string representation of the number, and detects whether the number uses [[Scientific notation#E notation|E notation]]. For this reason, when called from Lua, very large numbers or very precise numbers should be directly input as strings to get accurate results. If they are input as numbers, the Lua interpreter will change them to E notation and this function will return the precision of the E notation rather than that of the original number. This is not a problem when the number is called from #invoke, as all input from #invoke is in string format.