Finding two numbers in 9's complement arithmetic

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Discussion Overview

The discussion revolves around the process of finding two numbers in 9's complement arithmetic, specifically focusing on converting numbers into 9's complement form, performing arithmetic operations, and converting results back to decimal form. The conversation includes elements of homework-related queries and conceptual clarifications regarding complementary number systems.

Discussion Character

  • Homework-related
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes their conversion of the numbers 15,765 and -8,773 into 9's complement form, expressing confusion about summing these numbers and converting back to decimal.
  • Another participant questions why the 9's complement of +1 would differ from +1, suggesting a misunderstanding of the purpose of 9's complement.
  • A response emphasizes that the 9's complement of 1 is indeed 1, clarifying that the method is intended for representing negative numbers, not altering positive numbers.
  • Further elaboration is provided on the purpose and methodology of complementary number systems, including questions about the differences between 9's complement and 10's complement, as well as tradeoffs in computer implementations of 1's complement versus 2's complement.
  • A later post indicates that the original poster has resolved their confusion through additional reading on the topic.

Areas of Agreement / Disagreement

Participants express differing views on the understanding and application of 9's complement arithmetic, with some clarifying concepts while others question the methodology. The discussion does not reach a consensus on the initial confusion regarding the 9's complement of +1.

Contextual Notes

Some participants express uncertainty about the arithmetic operations in 9's complement and the implications of sign and magnitude representation. The discussion reflects a range of understandings about complementary number systems without resolving all questions raised.

brian.L
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Homework Statement


I have already converted the following numbers 15,765 and -8,773 into 9's complement form. Which gave me the result:

9's Complement of 15,765 = 99,999-84,234 = 84,234
9's Complement of -8,773 = 99,999-(-8,773) = 108,772

Now that I converted the following 5 digit numbers into 9's Complement, am starting to have problems dealing with finding the sum of the two numbers in 9's complement arithmetic and then converting it back into decimal form. I'm not sure if it has anything to do with Sign and magnitude, but can't seem to find a way around this problem.

Homework Equations


No equations.

The Attempt at a Solution


My solution so far is:
9's Complement of 15,765 = 99,999-84,234 = 84,234
9's Complement of -8,773 = 99,999-(-8,773) = 108,772
 
Last edited:
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brian.L said:

Homework Statement


I have already converted the following numbers 15,765 and -8,773 into 9's complement form. Which gave me the result:

9's Complement of 15,765 = 99,999-84,234 = 84,234
9's Complement of -8,773 = 99,999-(-8,773) = 108,772

Now that I converted the following 5 digit numbers into 9's Complement, am starting to have problems dealing with finding the sum of the two numbers in 9's complement arithmetic and then converting it back into decimal form. I'm not sure if it has anything to do with Sign and magnitude, but can't seem to find a way around this problem.


Homework Equations


No equations.



The Attempt at a Solution


My solution so far is:
9's Complement of 15,765 = 99,999-84,234 = 84,234
9's Complement of -8,773 = 99,999-(-8,773) = 108,772

Why would the 9's complement of +1 be something different than +1 ?
 
phinds said:
Why would the 9's complement of +1 be something different than +1 ?

What do mean? I'm not clear of what you are trying to point out.
 
brian.L said:
What do mean? I'm not clear of what you are trying to point out.

What I'm trying to point out is that the 9's complement of 1 is 1. 9's complement is a method for representing negative numbers as though they were positive numbers NOT a method for messing up positive numbers.
 
Actually, that was a bit brief.

What I really mean is that you seem to misunderstand the both the purpose and the methodology of complementary number systems and I suggest that you read up on them.

WHY would we want to represent a negative number as a positive number ?

HOW do we choose to do it (what's the difference between 9's complement and 10's complement) ?

what are the tradeoffs in implementing a computer with 1's complement vs 2's complement ?
 
phinds said:
Actually, that was a bit brief.

What I really mean is that you seem to misunderstand the both the purpose and the methodology of complementary number systems and I suggest that you read up on them.

WHY would we want to represent a negative number as a positive number ?

HOW do we choose to do it (what's the difference between 9's complement and 10's complement) ?

what are the tradeoffs in implementing a computer with 1's complement vs 2's complement ?

Sorry, for the late reply. I have just completed the question as well as other questions connected to 9's complement. Can't believe I got stuck on such a simple problem. Turns out a little reading on the topic helped out a lot.
 
brian.L said:
Sorry, for the late reply. I have just completed the question as well as other questions connected to 9's complement. Can't believe I got stuck on such a simple problem. Turns out a little reading on the topic helped out a lot.

Glad to hear it.
 

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