Can i make arduino save changes after log off

Hi guys
I have project on arduino nano board.
I upload the code and in the code there is variable that every time i click on button the number of the variable Decreased... After i turnd of the arduino the number of the variable go back to 0 ... There is any way to make the variable to save the current number without adding buttary...

You can use the Arduino's built-in [u]EEPROM[/u].

thank you very much, it was exactly what i needed.
And its work great..