Add field of decimal type Entity framework

Question

I have a Repair table in it I have Valuemade, Value and Total Value all of the decimal type. The Value field = Valuemaod + Value Library. However this returning 0. I am showing this in the Detail View when I click I will see the repair summary with its full price.

My Repair and Inspection/details

public ActionResult Detalhes(int id)
{
    decimal total = 0m;

    ConsertoVM model;
    using (Db db = new Db())
    {
        Conserto cons = db.Conserto.Find(id);
        decimal peca = cons.Pecas.ValorUnitatio;
        total += (cons.ValorMaoObra + peca);

        model = new ConsertoVM(cons);
    }

    return View(model);
}