Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have two different terms contributing to a sum. One is positive and one is negative(-0.077 and 0.067) How do I note the contribution of these terms in percentage? 0.067/(-0.01) -> -670% doesn't make any sense.

Edit: I know that logically 0.067 is -670% of the sum but I need to measure the relative weight of a term in a sum. Is comparing the absolute values a way to do it?(i.e 0.067/(0.067+0.077))

share|cite|improve this question
You could do it in terms of absolute values; in that case, the 'total' is 0.077 + 0.067, and the the contribution of the positive part is 0.067/(0.077 + 0.067) = 46,5 %. – Gerben May 3 '11 at 11:50

If you are willing to say that, in the sum $(-6)+(-4)=-10$, the minus six contributes 60% of the sum and the minus four 40%, then logically you should be prepared to say that, in the sum $(-0.077)+0.067=-0.1$, the $-0.077$ contributes 770% and the $+0.067$ contributes -670%.

But it would probably be better not to attempt say anything like this, to avoid confusion.

share|cite|improve this answer
This is a good demonstration of the loss of precision caused by subtraction. If you make a small percentage change in one of the summands, you make a large percentage change in the sum. The -670% and 770% figures are one way to represent that. – Ross Millikan May 3 '11 at 12:54
While this is logically true, it is not useful in my case. – Atilla Filiz May 3 '11 at 14:51

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.