Talk:Method of complements

message: I never really heard about Ten's complement, Nine's complement etc. until today, so I am probably not the one to tidy up this article. I found a decent brief explanation of them for anyone else who wants to try. Someone who's better at math, please give it a look. -- Wapcaplet 01:50, 7 Nov 2003 (UTC)
thread_title: [Untitled]

message: I don't think "nines' complement" is correct. The system works by finding the complement of each digit with respect to a value of nine, and there need not be multiple nines involved. The nine's complement of 3, for instance, is 6. It works similarly to two's complement, which works by finding each digit's complement with respect to the value 2. If there are no objections within a few days, I will revert. -- Wapcaplet 18:11, 18 Nov 2004 (UTC)
replies: text: I strongly agree.  But I notice that nothing has happened since November of last year.  Do you want to do this or shall I? Rick Norwood 19:21, 12 September 2005 (UTC)
replies: text: I think the text in the last paragraph of the Numeric Complements section is accurate. But I wrote it, so please correct it if not. I've only seen the topic addressed in one place, Knuth's The Art of Computer Programming (volume 2, section 4.1). See also Talk:Signed number representations. Logical as his argument seems to me, if another author has a different opinion, I'll consider it. Of course, language is what writers use, and a lot of them use nine's, whether Knuth agrees with it or not! --Rick Sidwell 01:49, 13 September 2005 (UTC)

text: Knuth is a man with strong opinions, some of them correct. Rick Norwood 14:32, 13 September 2005 (UTC)
thread_title:  Nine's vs. nines' 

message: I removed the following incorrect text:
:The n's complement of m is n - m.  For example, the ten's complement of 7 is 3; the one's complement of 1/3 is 2/3, the hundred's complement of 28 is 72.
It's true that the ten's complement of 7 is 3, and if you consider "28" a single digit in base 100, I suppose it's hundred's complement is "72". But the ten's complement of 28 is also 72, not -62, and the ten's complement of 007 is 993. And ones complement (no matter where you put the apostrophe) only makes sense in base 2; the example would be something like the ones' complement of 01/11 is 10/11, which may look like 1/3 and 2/3 converted to binary until you add more digits and get 0001/0011 and 1110/0011. --Rick Sidwell 00:41, 14 September 2005 (UTC)
replies: text: What is going on here is that the same word, "complement", is used in two very different contexts, computer science and elementary education.  I'll move the way the word is used in elementary education to the proper section.  Maybe we should split the article, and expand the education section with more examples of how complements are being used to teach subtraction. Rick Norwood 12:28, 14 September 2005 (UTC)
thread_title:  Deletion 

message: The article never explains zero, and specifically negative zero.  There are two solutions computers use for negative zero. One is to always compare equal to positive zero, and the other is not to generate one, given no inputs are negative zero. The latter case is easily done by building the logic of a ones' complement subtractor, and do addition by adding the complement. The article might mention this. Gah4 (talk) 20:45, 9 September 2020 (UTC)
thread_title:  zero 

message: The article mentions decimal, and then all the examples are nines' complement. Can we have a ten's complement example?  I wanted to link to this one. Gah4 (talk) 05:50, 28 October 2023 (UTC)
thread_title:  ten's complement