"luma " <email@example.com> wrote in message <firstname.lastname@example.org>... > I mean that the integer of x=156 and I need only 8 bit to represent the no. in good accuracy and x=0.102 the fractional could be represent good accuracy in 7 bit only . and then I don't need more than (8+7=15) 15 bit to represent x . - - - - - - - - - You have (more or less) indicated that you know how to calculate the number of bits required to store a number like 156.102 . However, it isn't at all evident what you are attempting to find out in this thread. What do you want to learn that you don't already know? As dpb asks, please give us "complete details". You have yet to do that!