you most likely have a calculation resulting in a fraction of 0.12 after the point which is 3/25 and 25=5^2 can't be coded without loss in a binary system.

Additionally Perl does some DWIM magic to hide minor errors, such that a printed 0.12 is not necessarily == 0.12 .

solution:

To calculate dollars "accurately" with 2 decimal places, you need
to calculate right from the beginning in cents as integers!

So just calculate with integers in the desired accuracy and shift the decimal point afterwards!

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