title: How do I subtract a certain number of minutes from a `DateTime` value?
body: <p>In the following code, instead of current system time, I want to subtract 5 minutes as integer I from <code>datetime.now().tostring()</code>. So the warning can be played 5 minutes before the system time matches the time in labeltext1. </p>
  
  <pre><code>private void timer1_Tick(object sender, EventArgs e)
  {
      label_time1.Text = DateTime.Now.ToString();
      mplayer = new SoundPlayer();
      mplayer.SoundLocation = (@"c:\users\woolsvalley\documents\visual studio 2015\Projects\WindowsFormsApplication17\WindowsFormsApplication17\Alarm.wav");
      if ((DateTime.Now.ToString("hh:mm tt") == ((textBox_ordertostart.Text))))
      {
          mplayer.Play();
          pbuilder.ClearContent();
  
          pbuilder.AppendText("Order time for" + "" + comboBox_suburb.SelectedValue + "Start in" + 5 + "minutes");
          txt2speech.Speak(pbuilder);
      }
  }
  </code></pre>