int sum = Class1.Add(5, 10); // sum now equals 15
double sum = Class1.Add(2.5, 3.75); // sum now equals 6.25This example uses Class1's Add method to add the values 2.5 and 3.75 together, and then stores the result in the variable "sum". This Class1 most likely belongs to a package or library which provides mathematical operations commonly used in C# programming.