How Do You Calculate Investment Percentage Changes Correctly?

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Discussion Overview

The discussion revolves around calculating percentage changes in investment values, specifically focusing on how to determine percentage gains and losses based on different initial and final amounts. Participants explore the nuances of these calculations, including the implications of starting and ending values.

Discussion Character

  • Mathematical reasoning
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant presents two methods for calculating percentage loss, leading to different percentage results, and seeks clarification on which method is correct.
  • Another participant emphasizes that percentage change is always relative to the initial amount, providing calculations for both loss and gain scenarios.
  • There is a discussion about the asymmetry in percentage changes when moving from a higher to a lower value compared to moving from a lower to a higher value.

Areas of Agreement / Disagreement

Participants generally agree on the method of calculating percentage changes relative to the initial amount, but there is a recognition of the differing results when calculating gains versus losses, indicating some level of disagreement or confusion regarding the implications of these calculations.

Contextual Notes

Participants express uncertainty about the correct interpretation of percentage changes, particularly in how they apply to different scenarios of investment values.

grandnat_6
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Hi,

I think I confused myself. Must be working too hard or something.

I trying to find the percentage gain or loss of an investment.

example:

1. orginal investment $10000.00 today $9,500.00

9,500.00/10,000.00 = .95*100 = 95%

Therefore I have 95% of my orginal amount or (100%-95%)= 5% loss.

10,000.00*-5%= -500

10,000.00-500= 9,500.00

Or:

10,000.00-9,500.00= 500.00

500.00/9,500.00= .05263*100=5.263%

9500*5.263=500

500+9,500.00= 10,000.00

Please straighten me out on this! They both seem to get me the correct answer but the percentages are different, which one is correct?

What if I started out with $9,500.00 and today it's $10,000.00?

Thanks.
 
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grandnat_6 said:
Hi,

I think I confused myself. Must be working too hard or something.

I trying to find the percentage gain or loss of an investment.

example:

1. orginal investment $10000.00 today $9,500.00

9,500.00/10,000.00 = .95*100 = 95%

Therefore I have 95% of my orginal amount or (100%-95%)= 5% loss.

10,000.00*-5%= -500

10,000.00-500= 9,500.00

Or:

10,000.00-9,500.00= 500.00

500.00/9,500.00= .05263*100=5.263%

9500*5.263=500

500+9,500.00= 10,000.00

Please straighten me out on this! They both seem to get me the correct answer but the percentages are different, which one is correct?

What if I started out with $9,500.00 and today it's $10,000.00?

Thanks.


UIt is not the same way up as way down in percentages:

if you began with $10,000.00 and after some time you have $9, 500.00 then you've lost 5% of your original invesment, as
$$\frac{9,500}{10,000}=0.05\Longrightarrow 0.05\cdot 100 \%=5\%\,\,\text{loss}$$
as the final amount is less than the first one.

Had you begun with $9,500.00 and after some time you had $10,000,, then you'd have won
$$\frac{10,000}{9,500}=1.05263\Longrightarrow (1-1.05263)\cdot 100\%=5.6263\%\,\,\text{profit}$$

DonAntonio
 
The "percentage change" is always relative to the initial amount. Going from 10000 to 9500 is a decrease of 500 so a percentage change of -500/10000= -.05 or -5% of 10000.

But an increase from 9500 up to 10000 is an increase of 500 and so a percentage change of 500/9500= .0526 or 5.26%.
 
Thanks for the help! I understand now.
 

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