static void Main(string[] args)
{
Maths math = new Maths();
Console.WriteLine("Въведете число 1");
math.Number1 = int.Parse(Console.ReadLine());
Console.WriteLine("Въведете число 2");
math.Number2 = int.Parse(Console.ReadLine());
math.SetStrategy(new AddStrategy());
Console.WriteLine($"+ {math.Calculate()}");
math.SetStrategy(new SubstractStrategy());
Console.WriteLine($"- {math.Calculate()}");
}