Real number

I am not yet sure how to define real numbers. Many irrational numbers (e.g. ${\sqrt {2}}$ and Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \pi} ) are in fact real, but the standard definition of the reals involves infinite nonsense.

Examples

Any fraction.

Any algebraic number like Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \sqrt{2}} .

Pi

e

The output of the following computer program

digit(int i): if

 
digit(int i): 
if (suthaweou) 
return 0