Precision 90 is a scientific calculator designed for engineers, scientists, teachers, and students. It accurately calculates complex and lengthy mathematical formulas with ease.

One thing that stood out to me is that it's programmed in C#, which means that it's optimized for efficient performance. Additionally, all calculations are done in a proprietary data type, which enhances its precision. No matter how complex the mathematical formula may be, this calculator can handle it with ease.

Another great feature of this calculator is that it keeps a detailed calculation history, which can be stored into a text file or printed out. It also has ten variables or constants available for storing frequently used numbers. It even comes preloaded with a comprehensive Common Constants list that includes all the fundamental constants, and an unlimited User Constants list.

What I found most remarkable about the Scientific Calculator Precision 90 is that its precision can reach up to 90 digits. It has a wide range of sophisticated mathematical functions like Trigonometric, Hyperbolic, Inverse, and Combinatorial functions. It also has special numbers like NaN, Uncertainty, and Infinity.

This calculator follows a classical approach when estimating the uncertainty of f(x) calculation, which contributes to the quality and accuracy of its output. It even includes advanced mathematical functions like Gamma function, Lower/Upper Incomplete Gamma function, Beta function, Incomplete Beta Function, and Sine integral function.

Finally, the calculator includes a summation and product operator that allows for four levels of nesting. Overall, I would highly recommend the Scientific Calculator Precision 90 to anyone in need of a reliable and precise tool for performing complex mathematical calculations.

Version **1.0.1.2**:
improvement

Version **1.0.0.6**:
Trial scheme improvement

Version **1.0.0.5**:
Speed improvement

Version **1.0.0.4**:
Corrections

Version **1.0.0.0**:
N/A