// C# Extension Method
// Doc: https://csharp-extension.com/en/method/1002623/timespan-ago
// @nuget: Z.ExtensionMethods
using System;
public class Program
{
public static void Main()
var timeSpan = new TimeSpan(1, 0, 0, 0);
// C# Extension Method: TimeSpan - Ago
DateTime value = timeSpan.Ago(); // return yesterday.
Console.WriteLine(value.ToFullDateTimeString());
}