I'm amazed at how long I've gone with the misconception that: Exact Numbers = Integers union Rationals Inexact Numbers = Floating Point numbers (Frankly, I never really thought much about what infinities were. I assumed they were a separate, distinct type). When I saw in the docs for round that it returns an integer, and I was getting an inexact number, I was sure it was a mistake. Thanks for helping me straighten out my thinking on this. I can see how you might want to test an inexaxct number for whether it is the floating point approximation of an "integer", so that makes sense. Still seems weird and inconvenient for round to give you back an inexact integer rather than an exact one, but I can see now how this behavior matches the standard. Thanks, Mark