How can I console.log the last value from a for loop?

I am trying to get the last value from a for loop. I have tried a number of things including pop() and lastchild but all I get is the “This is not a function” error. Can someone offer any help with this?

  var totalAppointments =  Array.from(recordXmlNode.children[1].innerHTML);

  var numberAppointments = totalAppointments.map(Number);


  for (let i = 0; i < numberAppointments.length; i++) {
       sum += numberAppointments[i];
  }

  console.log(sum);

Thanks