using System;

namespace Singleton {  

    class Program {  

        static void Main(string[] args) {  

            Calculate.Instance.ValueOne = 10.5;  

            Calculate.Instance.ValueTwo = 5.5;  

            Console.WriteLine("Addition : " + Calculate.Instance.Addition());  

            Console.WriteLine("Subtraction : " + Calculate.Instance.Subtraction());  

            Console.WriteLine("Multiplication : " + Calculate.Instance.Multiplication());  

            Console.WriteLine("Division : " + Calculate.Instance.Division());  

            Console.WriteLine("\n----------------------\n");  

            Calculate.Instance.ValueTwo = 10.5;  

            Console.WriteLine("Addition : " + Calculate.Instance.Addition());  

            Console.WriteLine("Subtraction : " + Calculate.Instance.Subtraction());  

            Console.WriteLine("Multiplication : " + Calculate.Instance.Multiplication());  

            Console.WriteLine("Division : " + Calculate.Instance.Division());  

        }  

    }  

    public sealed class Calculate {  

        private Calculate() {}  

        private static Calculate instance = null;  

        public static Calculate Instance {  

            get {  

                if (instance == null) {  

                    instance = new Calculate();  

                }  

                return instance;  

            }  

        }  

        public double ValueOne {  

            get;  

            set;  

        }  

        public double ValueTwo {  

            get;  

            set;  

        }  

        public double Addition() {  

            return ValueOne + ValueTwo;  

        }  

        public double Subtraction() {  

            return ValueOne - ValueTwo;  

        }  

        public double Multiplication() {  

            return ValueOne * ValueTwo;  

        }  

        public double Division() {  

            return ValueOne / ValueTwo;  

        }  

    }  

}