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From: Karl Ratzsch <mail.kfr@gmx.net>
Newsgroups: comp.graphics.apps.gnuplot
Subject: Re: incorrect arithmetik?
Date: Tue, 12 Jan 2016 14:19:20 +0100
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Am 12.01.2016 um 11:40 schrieb Jörg Buchholz:
> I can not found the solution to the following problem:
> 
> b=7.2-6.9
> c=8.2-7.9
> 
> show variables

> b = 0.3
> c = 0.299999999999999
> 
> Why is c not 0.3?

Floating point arithmetics. Most decimal fractions cannot be represented
exactly by a binary float variable.

8.2 is 1000.00110011....
7.2 is 111.11100110011....

If the two errors add up in one direction, the result of your
subtraction will be closer to a value that is in fact off by 1 in the
least significant digit.

  Karl