How to resolve this error

CREATE TABLE [dbo].[Deduction_1](
	[Id] [bigint] IDENTITY(1,1) NOT NULL,
	[Ded] [numeric](18, 0) NOT NULL,
 CONSTRAINT [PK_Deduction_1] PRIMARY KEY CLUSTERED 
(
	[Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

using System;
using System.Web;
using System.Data.Entity;

namespace ASPNETMVCApplication.Models
{
    public class BookDBContext:DbContext
    {
        
        public DbSet<book1> Deduction_1 { get; set; }
    }
}

using System;
using System.Web;

namespace ASPNETMVCApplication.Models
{
    public class Book1
    {
        public Int64 Id { get; set; }
        public Decimal Ded { get; set; }
        

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using ASPNETMVCApplication.Models;

namespace ASPNETMVCApplication.Controllers
{
    public class DeductionController : Controller
    {
        BookDBContext _db = new BookDBContext();

        //
        // GET: /Deduction/

        public ActionResult Index()
        {
            var deductions = from deduction in _db.Deduction_1
                             select deduction;

            return View(deductions.ToList());
        }

        public ActionResult Create()
        {
            return View();
        }

        [HttpPost]
        public ActionResult Create(FormCollection collection)
        {

            Book1 deduction = new Book1();
            if (ModelState.IsValid)
            {
                deduction.Ded = Convert.ToDecimal(collection["Ded"].ToString());


                _db.Deduction_1.Add(deduction);
                _db.SaveChanges();

                return RedirectToAction("Index");
            }
            else
            {
                return View(deduction);
            }

        }
    }
}