"XII" is a Roman numeral that represents the number 12. In Roman numerals, "X" represents the number 10, and "II" represents the number 2. When you combine the two, you get "XII," which represents the number 12. Roman numerals are a numerical system that was used in ancient Rome and is still used today in some contexts, such as for numbering chapters in books or for indicating the year in some formal documents. The system uses letters from the Latin alphabet to represent numbers, and it has its own set of rules and conventions for reading and writing numbers.