The Crystal Programming Language Forum

Why is 2.0 - 1.8 = 0.199... instead of 0.2

Why does 2.0 - 1.8 not result in 0.2?

pp! 2.0 - 1.8
2.0 - 1.8 # => 0.19999999999999996
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Wikipedia has info on it: https://en.wikipedia.org/wiki/Floating-point_arithmetic#Accuracy_problems

TL;DR: Floats are less precise than one would expect. It’s not specific to Crystal.

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Thanks

Also, Ruby prints it right, but Ruby uses another algorithm to print floats. You could open an issue/bug if you’d like to.

Oh, I spoke too soon, Ruby also prints it like Crystal :blush: