# Thread: simple mathematic calculation

1. Registered User
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Aug 2005
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Kuala Lumpur, MY
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## Unanswered: simple mathematic calculation

hie all

i created a test table and inserted '54' into nm1 column and '62' into nm2 column

i wanted to do a calculation which is 'nm2-nm1/nm1' in other words (62-54)/62 which should return 0.12

but its returning some other result...

any help ?

2. Moderator.
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Sep 2002
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What result did you get? Not 61 by any chance?

If you look carefully at your calculation you will see it is actually 62-54/54, which is evaluated as 62-(54/54) which is 61.

3. Registered User
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Sep 2004
Location
London, UK
Posts
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nm2-nm1/nm1 is not the same as (62-54)/62! Check the rules for arithmetic precedence.

This will be the same in other languages, for example (just for fun) in Korn shell:

Code:
```/Users/williamr: float nm1=54
/Users/williamr: float nm2=62
/Users/williamr: echo \$(( nm2-nm1/nm1 ))
61
/Users/williamr: echo \$(( (nm2-nm1)/nm2 ))
0.129032258065```
Update: Tony beat me to it.

I've just noticed that your formula varies:

Originally Posted by shatishr
i created a test table and inserted '54' into nm1 column and '62' into nm2 column.

i wanted to do a calculation which is 'nm2-nm1/nm1' in other words (62-54)/62
If nm1=54 and nm2=62, shouldn't that be (62-54)/54?

Code:
```/Users/williamr: echo \$(( (nm2-nm1)/nm1 ))
0.148148148148```
Last edited by WilliamR; 01-21-06 at 11:27.

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