fracElementElementElement functions can be customized with set and show rules.
Element
Element functions can be customized with 
set and show rules.A mathematical fraction.
Example
$ 1/2 < (x+1)/2 $
$ ((x+1)) / 2 = frac(a, b) $

Syntax
This function also has dedicated syntax: Use a slash to turn neighbouring expressions into a fraction. Multiple atoms can be grouped into a single expression using round grouping parenthesis. Such parentheses are removed from the output, but you can nest multiple to force them.
ParameterParameterParameters are input values for functions. Specify them in parentheses after the function name.
Parameter
Parameters are input values for functions. Specify them in parentheses after the function name.
numRequiredRequiredRequired parameters must be specified when calling the function.PositionalPositionalPositional parameters can be set by specifying them in order, omitting the parameter name.
Required
Required
Required parameters must be specified when calling the function.
Positional
Positional
Positional parameters can be set by specifying them in order, omitting the parameter name.
The fraction's numerator.
denomRequiredRequiredRequired parameters must be specified when calling the function.PositionalPositionalPositional parameters can be set by specifying them in order, omitting the parameter name.
Required
Required
Required parameters must be specified when calling the function.
Positional
Positional
Positional parameters can be set by specifying them in order, omitting the parameter name.
The fraction's denominator.