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Message: [QUOTE="Markus, post: 4446129"] Peeling one layer of the onion, they differ because: irb(main):033:0> printf "%20.15f",(134.45 * (1.0/0.1)) 1344.500000000000000=> nil irb(main):034:0> printf "%20.15f",(134.45/0.1) 1344.499999999999773=> nil I suppose this is not unexpected (my mama warned me 'bout floats) but it is a little unexpected--no, I'm wrong, 1/5 is a repeating decimal base 2, so it's perfectly expected. The tricky bit is, which form (if either of them) will always (or at least, more generally) give the correct result? I can't see off hand that either will be intrinsically "better" but I could be missing a point. I suspect (SWAG) that the hybrid: def to_the_nearest(n) if self.abs < 1.0 (self/n).round/n else m = 1.0/m (self*m).round/m end end would do better than both, but I haven't tested it. -- Markus P.S. Mine has mostly been tested on values < 1.0, thus my suspicion that it works well in that domain. Typing this though, I realize that it was tested FOR CONFORMANCE WITH A PRE-EXISTING SYSTEM* which itself may have been buggy. * Think 25 year old spaghetti FORTRAN, then sigh in bliss realizing that your imagination is much nicer than the ugly facts. [/QUOTE]