Free Calculator. You can use Calculator to perform any of the standard operations for which you would normally use a handheld calculator. Free Calculator. You can use Calculator to perform any of the standard operations for which you would normally use a handheld calculator. Calculator performs basic arithmetic, such as addition and subtraction, as well as functions found on a scientific calculator, such as logarithms. The game interface is quite simple so even if you are a beginner you can use it without any trouble.