Checks the user number is a prime number.

The calculator can calculate the area of a parallelogram.

The calculator calculates the volume of a cylinder with using of height and area.

Number of square-triangle has the properties of a square and a triangular number.          

In math calculator calculate triangular number is a number that can be represented as the sum of consecutive integers starting.    

Tetrahedral numbers are the natural numbers, for which it is possible to construct a tetrahedron formnego of bullets. They are a special case of the pyramidal numbers.        

The calculator calculates the approximate value of the motor using Stirling's formula      

Specifies the basic operation of the two sets