Hi, I have just scared. I expect that is here with some mathematical and physical constants, and get for a particular value for my double variable "ExpTerm = 2.22184e-09" out. The next step, I reckon (x is also a double) Code: x = 1 - expTerm; court <<"1 - expTerm = "<<x <<endl; However, the result gives me a "1 - 1 from expTerm ="! In such an accuracy could, of course I completely forgot my account immediately. How can I increase the accuracy?