Why 0.2+0.09 = 0.29000000000000004?

[lliu1871]

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

[Sukera]

PSA: floating-point arithmetic

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:

https://0.30000000000000004.com

[lliu1871]

Thanks for the detailed explanation. This is very helpful.

[LaurentPlagne]

You might found this package https://github.com/JuliaMath/DecFP.jl interesting

[lliu1871]

This is great. Thank you!