Bummer! Did you call the model builder's 'Entity' method?

using System.Data.Entity;

namespace Treehouse.CodeChallenges
{
    public class Context : DbContext
    {
        public Context()
        {
            Database.SetInitializer(new DropCreateDatabaseAlways<Context>());
        }

        public DbSet<Course> Courses { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
           modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
           modelBuilder.Conventions.Remove<DecimalPropertyConvention>();
           modelBuilder.Conventions.Add(new DecimalPropertyConvention(4,3));

          modelBuilder .Entity<CourseStudent>().Property(c => c.Grade).HasPrecision(4,3);

        }
    }
}