Sure, but the inexactness of this modulus operation would not be any more unpredictable than all other kinds of float inexactness. Unless you're talking about the case where you don't know whether your operands are ints or floats. But in that case, there are tons of other unpredictabilities. For example, a + b will round when adding (sufficiently large) integers-represented-as-floats while it will never round for integers. So if you take floating-point math seriously, knowing that you're actually dealing with floats is the first step.