C# .Net Get First and Last Date in a specific Week

FirstLastDayInWeek.cs

static List<DateTime> FirstLastDayInWeek(int Year, int month, int WeekNumber)
{
    WeekNumber -= 1;
    DateTime start = new DateTime(Year, month, 1).AddDays(7 * WeekNumber);
    start = start.AddDays(-((int)start.DayOfWeek));
    return Enumerable.Range(0, 7).Select(num => start.AddDays(num)).ToList()
        .Where(w => w.Year == Year && w.Month == month).ToList();
}

// to use it

List<DateTime> dates = FirstLastDayInWeek(2022, 2, 1).ToList();
Console.WriteLine($"First: {dates.First().ToString("yyyy-MM-dd")}");
Console.WriteLine($"Last: {dates.Last().ToString("yyyy-MM-dd")}");