You will see Hex (Hexadecimal), Dec (Decimal), Oct (Octal) and Bin (Binary) radio buttons. These are used for converting numbers between these numbering systems.

While the decimal numbering system allows any digit in a number to have any of ten values (0-9), digits in hexadecimal numbers can have 16 (0-F), digits in octal numbers only eight (0-7) and ...

For the 15,340 example this produces 3BEC in hex. You may wish to convert the date back to decimal using a calculator or other application to ensure the result is correct.