The Base Converter
Note: If you want to deal with hexadecimal numbers (base 16), add a '0X' (Zero, not O) in front of the number. Eg: "FF" becomes "0XFF"!Try not to use extremely large numbers unless your computer's speed is over 2000 mHz! The largest base you should use is 40, which is quite large already. You can also use bases larger than 40 but sometimes they won't work...
To multiply a number in a certain base, just convert the numbers into base 10 first, then convert them back into the required base!