Not unless I've missed it to. If the value of a number is -3, it's -3, not 3 with some negative sign kept elsewhere that may or may not change it. That's a bit of a freaky design. Although, I'd have to check with an accounting friend for the details, I think there is a method of accounting whereby you designate everything as a value and then describe the value as either a credit or debit, + or -, maybe that's what you're dealing with.