Mistake in calculations

[Reza1607]

Hello
When calculating the following, the calculation is wrong

> console.log(.58*100)
57.99999999999999  // !!!!!!!!
> console.log(.57*100)
56.99999999999999  // !!!!!!!!
> console.log(.56*100)
56.00000000000001  // !!!!!!!!
> console.log(.55*100)
55.00000000000001  // !!!!!!!!
> console.log(.54*100)
54
> console.log(.53*100)
53
> console.log(.52*100)
52

Why?

• Version: 7.5.0
• Platform: Linux 4.10.0-35-generic Gitter chat room? #39-Ubuntu SMP Wed Sep 13 07:46:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

[apapirovski]

Hi @Reza1607, this is a common problem in languages that implement IEEE 754 floating-point arithmetic. See this handy site for more info: http://floating-point-gui.de/ and more specifically http://floating-point-gui.de/basic/

In general, the appropriate place to ask this question would be in https://github.com/nodejs/help or StackOverflow. This tracker is for bug reports and feature requests related to Node core.

[tniessen]

Similar issues have been reported numerous times and are present in all languages implementing IEEE 754 floating point numbers. Arbitrary precision arithmetic is not supported at the moment.