note jepri You say:<P> <i> ps. why would I want to read a book on number theory to understand why a basic operator behaves the way it does?</i><P> The answer is "So you know what you are talking about". I admit I was too quick off the gun as well, however. After some further research I found that the modulo function was devised by Abel in the 1700's to allow him to study large and complicated groups with only pencil and paper. <P> Modulo is hardly a basic operator. It's just a basic operator for you because you've only ever used it in simple situations.<P> Computer implementations of functions are usually nasty bastardisations of real math functions. This is why the original poster mentioned Knuth, who did a lot of work involving math and computers.<P> Incidentally, 'proof by random web pages' is a poor way of proving that you are right.<P> <p>____________________<BR> Jeremy<BR> I didn't believe in evil until I dated it. 87384 88604