This might be true on really weird platforms, but with IEEE-754 floating point this isn&#x27;t true. Integers within a big range are exactly representable without any rounding error. Doing floor((float(13) + float(13))&#x2F;2.0) should be exactly 13. It is entirely possible that the weird platform was supposed to be using IEEE-754 arithmetic but had a buggy math library (depressingly common).