Asked my son to see how the computer calculates. It's actually quite interesting :) program ab; var a:real; begin a:=0.499999999999; writeln(round(a)); readln; end. It displays 0 on the screen. If you change the variable 'a' from 0.49 to 0.499999999999... When you add one or more nines to the right of the variable, it starts displaying 1 :) It would be interesting to hear what vbn has to say. For starters, he could at least repeat the experiment on his computer and with his version of Delphi. We have some old DOS Pascal.