Syntax for this kind of filter allows searching for numerical values (integer or floating point, for example 4711 or 3.14) or a value-range.
 
Possible syntaxes in the hover text of a specific filter:
 

1. Syntax[NUM]: 314
   
2. Syntax[NUM]: 3, -14, 1-5, 9-
   

The first syntax only allows exact searches, while the second syntax also allows to search for values that lies in ranges of numeric values. The '-' is used as a special character to indicate a range:

• -14 = search for values <= 14
  
• 9- = search for values >= 9
  
• 1-5 = search for values between 1 and 5 (inclusive)
  

As '-' is a special character it can't be used to indicate a negative sign. Therefore if ever needed (and that is a rare case), you use single quotes to escape the special meaning. For example: '-3'-9 searches for values between -3 (three negative) and 9.