function run_calculation() {
  var sum = $('input.sum').sum();
  var principle_loan = $('input#principle_loan').parseNumber();
  var per_diem_interest = $('input#per_diem_interest').parseNumber();

  var amount_financed = (principle_loan - sum);
  var high_cost_fees = (sum - per_diem_interest);
  var percentage = Math.round((high_cost_fees / amount_financed)*1000000)/10000;

  $('span#total_points_fees').text(sum);
  $('span#amount_financed').text(amount_financed);
  $('span#high_cost_fees').text(high_cost_fees);
  $('span#percentage').text(percentage);
}
$(function(){
  $('input').bind('keyup', function(){
    run_calculation();
  });
  run_calculation();
});