Why can't you just do Two BigInts seperated by a decimal point, and when you need to add, you can add the Whole numbers by themselves, then after the decimal point, just multiply them by the decimal place, do addition, then divide them again. Does that make sense? basically use scientific notation. Then leading zeros make no difference, and you don't have to worry about it.

(as part of this, can't you put an internal property or variable which will keep track of the number of decimal places?) it can simply update itself, that way you can modify leading zeros whenever, and still be able to simplify addition and subtraction.

I hope I'm making sense.