Ruby Math - BigDecimal

Let's have a look at this example:

1.2 + 1.0 == 2.2 (returns true)
but if I do:



1.2 - 1.0 == 0.2 (returns false)
Hmmm ... strange. This comes down to the way computers generally store numbers in binary but not in base10 system. The system that human generally work and think in.



Anyway, to fix this problem, I use Ruby built-in class BigDecimal



require 'bigdecimal'

require 'bigdecimal/util'

1.2.to_d - 1.0.to_d == 0.2.to_d (returns true)


Reference:

http://www.ruby-doc.org/stdlib/libdoc/bigdecimal/rdoc/classes/BigDecimal.html
http://ramblingsof.justinwinkler.com/when-crap-just-doesnt-add-up

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