# Why 0.2+0.09 = 0.29000000000000004?

**URL:** <https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750>\
**Category:** New to Julia\
**Tags:** numbers\
**Created:** [September 6, 2021, 1:15pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750 "2021-09-06T13:15:17Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![lliu1871](https://avatars.discourse-cdn.com/v4/letter/l/3e96dc/32.png) [@lliu1871](https://discourse.julialang.org/u/lliu1871)\
**Post date:** [September 6, 2021, 1:15pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750/1 "2021-09-06T13:15:17Z")

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I am new to Julia. I typed 0.2+0.09 in Julia and got 0.29000000000000004. could anyone explain it? Thanks.

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**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [September 6, 2021, 1:20pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750/2 "2021-09-06T13:20:12Z")

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> [@PSA: floating-point arithmetic](https://discourse.julialang.org/t/psa-floating-point-arithmetic/8678):
>
> Sometimes people are surprised by the results of floating-point calculations such as julia\> 5/6 0.8333333333333334 # shouldn't the last digit be 3? julia\> 2.6 - 0.7 - 1.9 2.220446049250313e-16 # shouldn't the answer be 0? These are not bugs in Julia. They’re consequences of the IEEE-standard 64-bit binary representation of floating-point numbers that is burned into computer hardware, which Julia and many other languages use by default. Brief explanation You can t…

Also, see:

> **[Floating Point Math](https://0.30000000000000004.com)**

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**Author:** ![lliu1871](https://avatars.discourse-cdn.com/v4/letter/l/3e96dc/32.png) [@lliu1871](https://discourse.julialang.org/u/lliu1871)\
**Post date:** [September 6, 2021, 1:28pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750/3 "2021-09-06T13:28:42Z")

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Thanks for the detailed explanation. This is very helpful.

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**Author:** ![LaurentPlagne](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/laurentplagne/32/10103_2.png) [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Post date:** [September 6, 2021, 2:00pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750/4 "2021-09-06T14:00:59Z")

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You might found this package [https://github.com/JuliaMath/DecFP.jl](https://github.com/JuliaMath/DecFP.jl) interesting

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**Author:** ![lliu1871](https://avatars.discourse-cdn.com/v4/letter/l/3e96dc/32.png) [@lliu1871](https://discourse.julialang.org/u/lliu1871)\
**Post date:** [September 6, 2021, 2:34pm UTC](https://discourse.julialang.org/t/why-0-2-0-09-0-29000000000000004/67750/5 "2021-09-06T14:34:41Z")

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This is great. Thank you!