Numbers and variables as subfunctions

A subfunction can be a number or a variable. This usually only makes sense, if the number or a variable subfunction is a subfunction of an other real function (like the addition). Variables must be defined in a Fib object above the function element, in which they are used (e. g. by a different function element).

Syntax number: $X$

Example number: $3$

Syntax Variable: $x$

Example Variable: $x$