Sorry to poke fun at you Volker, I didn't mean to offend you. It's just that this question actually has been asked several times, and quite recently too, so when you ask the same question it suggests you haven't used the search engine to find related threads, which is what most people do. When you then make a new thread about the same question it then requires the same answers to be written all over again, and usually by the same people who answered before. So it does get a bit tiresome. Yes you may be a beginner but the people answering aren't going to be beginners, or new to the question. I do recommend using the search feature, if you search for topics to do with floating point you'll probably find something along these same lines.