How to create instance of WCF DataContract class at client side

   [ServiceContract]
    public interface IArithmetic
    {
 
        // TODO: Add your service operations here
        [OperationContract]
        int Add();
 
        [OperationContract]
        int Sub();
 
        [OperationContract]
        int Mult();
 
        [OperationContract]
        double Div();
 

    }
 

    [DataContract]
    public class ArithData
    {
 
        private int numb1;
        private int numb2;
 
        [DataMember]
        public int Numb1
        {
            get{ return numb1;}
            set{ numb1 = value;}
        }
 
        [DataMember]
        public int Numb2
        {
            get{return numb2;}
            set{numb2 = value;}
        }
    }
}
 
public class Arithmetic : IArithmetic
    {
        ArithData objArithData = new ArithData();
        int numb1;
        int numb2;
 
        public Arithmetic()
        {
            numb1 = objArithData.Numb1;
            numb2 = objArithData.Numb2;
        }
 
        public int Add()
        {
            return numb1 + numb2;
        }
 
        public int Sub()
        {
            return numb1 - numb2;
        }
 
        public int Mult()
        {
            return numb1 * numb2;
        }
 
        public double Div()
        {
            return numb1 / numb2;
        }
 
    }
 
//my client side code

protected void Page_Load(object sender, EventArgs e)
        {
            int numb1 = Convert.ToInt32(this.txtnumb1.Text);
            int numb2 = Convert.ToInt32(this.txtnumb2.Text);
 
            ArithmeticFunc.ArithmeticClient ArithClient = new ArithmeticFunc.ArithmeticClient();
 
//I want to create instance of Datacontract - "ArithData" class here...so that i can pass numb1 and numb2 parameters to the ArithData Constructor.

        }