private void BtnClearAll_Click(object sender, RoutedEventArgs e)
        {
            Calculations.ClearFullMemory();
            TbCalculationProgress.Text = "";
            TbInputNumbers.Text        = "0";
            TbResultMemory.Text        = "";

            MemoryHasBeenCleared    = true;
            NoCalculationsYet       = true;
            UserCanDeleteLastNumber = true;
            NewCalculation          = true;
        }