Round decimal value using Math.Round function in ASP.Net MVC

Hi,

I have 2 dates

based upon that i am calculating difference

currently my requirement is that based upon that i am going to round of the value

my expeted o/ps

1)3.1234-3.12

2)3.45699-3.46

could you please help me

public JsonResult GetNoOfMonths(string psd, string ped)
{

    DateTime dtPSD = Convert.ToDateTime(psd);
    DateTime dtPED = Convert.ToDateTime(ped);
    int days = (dtPED - dtPSD).Days;
    double month = (days + 1) / 30.0;
    double d = Math.Floor(month * 100) / 100;
    return Json(d, JsonRequestBehavior.AllowGet);
         
}