number systems/signing

Hi /prog/

How does one represent negative numbers in hex/octal, e.g -15. Would the hex value be F1 or -0F? In the example i've been given it says -15 is F1, but I dont see how the sign is represented, shouldn't F1 be +241?

>>6
>>4-san isn't being pedantic, cockpouch. Two's-complement representation of negative numbers depends at the very least on how wide your shit is.
The only real answer, given what >>1-kun has bothered to tell us, is -F.