The number_format tag can be used to properly format numeric values.
For example
<cms:number_format '1234567890' />
The snippet above will output
1,234,567,890.00
The number to be formatted.
By default two numeric characters are outputted after the decimal point. This can be changed by this parameter.
<cms:number_format '1234567890' decimal_precision='0' />
will output
1,234,567,890
The default character used as the decimal point can be changed by this parameter.
The default character used as the thousand separator is the comma. It can be changed by this parameter.
The following snippet can be used to format a number in French notation
<cms:number_format '1234.56' decimal_character=',' thousands_separator=' ' />
Output -
1 234,56
It is a self closing tag and sets no variables of its own.