You are assuming that 0.1 is exactly represented. Since it is not, either 0.1 or 1-0.9 will be less than 0.1.

As to what you should do about it... that depends on what you are trying to accomplish. Whatever it is, you need to use some other approach. Often the alternative involves using integers as much as possible.
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"Folkes, Michael" <Michael.Folkes@dfo-mpo.gc.ca> wrote:

Perhaps somebody could clarify for me if the following is a floating point matter or otherwise, and how am I to correct for it? > floor(100*.1) [1] 10 > 100*(1.0-.9) [1] 10 > floor(100*(1-0.9)) [1] 9 Thanks! Michael_____________________________________________
Michael Folkes Salmon Stock Assessment Canadian Dept. of Fisheries & Oceans Pacific Biological Station 3190 Hammond Bay Rd. Nanaimo, B.C., Canada V9T-6N7 Ph (250) 756-7264 Fax (250) 756-7053 Michael.Folkes@dfo-mpo.gc.ca 	[[alternative HTML version deleted]]_____________________________________________
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