A handy fast reliable precise tool if you need to perform complex mathematical calculationsScientific Calculator Precision 81 is programmed in C#. All calculations are done in proprietary data type. The calculator handles mathematical formulas of any length and complexity. Calculation history can be stored into text file or printed. There are ten variables or constants available for storing often used numbers. Prebuilt Common Costants list with fundamental constants. Unlimited User Constants list. Precision of calculations is 81 digits. Trigonometric hyperbolic inverse and combinatorial functions. Special numbers NaN Uncertainty and Infinity. The calculator follows classical approach when uncertainty of f(x) calculation is estimated by formula max(derivative(f))*x*uncertainty(x) where maximum of function derivative is considered on interval x-uncertainty(x)x+uncertainty(x) and uncertainty(x)x*10^(-precision). Gamma function Lower Incomplete Gamma function Upper Incomplete Gamma function. Summation and product operator has three levels of nesting.