Hi every body I don't know why I don't have the float part of the temp var.
float temp; int H_Value; int L_Value; int value = 55; temp = value / 10; H_Value = (int)temp; L_Value = (int)(temp - H_value)*10;
The program behaves exactly right --- it's your expectation that's incorrect here. The bug in your program is that there's not a single manifest floating point number in it.
And note that this is all standard 'C' - nothing specifically to do with Keil. Therefore, in this case, reading the Keil Manual will not help you - because the Keil manual assumes that you already know ANSI 'C', so only goes into the implementation-specific details. You will need to refer to K&R, or another good 'C' textbook.