using System;

public class Program

{

    public static void Main()

    {

        var past = FutureOrPast(past: true, distanceInDate: 1);

        Console.WriteLine($"Will go back {past} in time");

        var furtherBack = FutureOrPast(past: true, distanceInDate: 3);

        Console.WriteLine($"Will go back {furtherBack} in time");

        var future = FutureOrPast(past: false, distanceInDate: 1);

        Console.WriteLine($"Will go forward {future} in time");

        var furtherForward = FutureOrPast(past: false, distanceInDate: 3);

        Console.WriteLine($"Will go forward {furtherForward} in time");

    }

    private static int FutureOrPast(bool past, int distanceInDate) => past ? (distanceInDate * -1) : distanceInDate;

}

​