帮忙写个代码

using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
int a = 100;
for (a = 100; a <= 350; a++)
{
if (a % 2 == 0)
{
Response.Write(a);
}
}
}
}

这是个很c#中100-350之间的偶数。如何统计这些数字的个数，还有如何统计100-350之间的偶数和与奇数和，要代码，大哥大姐们，帮帮忙，谢谢啦！！！