Why double becomes int?

When I run this code, I get output "System.Double, 3"

namespace NewApp 
{
    class Program
    {
        static void Main(string[] args)
        {
            double a = 1.0;
            double b = 2.7;
            a = Math.Round(b);
            Console.WriteLine(a.GetType() + ", " + a);
        }

    }
}

Why I see "3", if a is double variable and I supposed to see "3.0"?

>Solution :

It is still double. You are facing with 3 instead of 3.0 because of the way Console.write works. Use this as example

Console.WriteLine(DoubleConverter.ToExactString(a))