JSFiddle - React, Tailwind, and code Playground

HTML

<input placeholder="Total funds required" type="text" name="minus"   id="minus" />


  <select id="time" name="time"> 
   <option value="5" selected="selected">Term Duration</option>
  <option value="36">36 Months</option>
  <option value="48">48 Months</option>
  <option value="60">60 Months</option>
  <option value="84">84 Months</option>

   </select>

   <select id="interest" name="interest"> 
   <option value="0" selected="selected">Interest</option>
  <option value="7.9">7.9%</option>
  <option value="9.9">9.9%</option>
  <option value="12.9">12.9%</option>
  <option value="15.9">15.9%</option>

   </select>
 


  <div id="amount">

  </div>

  <button id="process">
  calculate 
  </button>

JavaScript

$('#time, #interest, #minus').change(function(){
    var time = parseFloat($('#time').val()) || 0;
    var interest = parseFloat($('#interest').val()) || 0;
    var minus = parseFloat($('#minus').val()) || 0;
    var yearly = 12;
		var y = 0.01;
    var makear = (interest / yearly * y);
    var makean = (time); // 180
    var addone = 1; //+1
    var addonetoexpo = (makear + addone); 
    var solved_expo = Math.pow(addonetoexpo, makean);
    var solve_top = (makear * solved_expo); 
		var solve_bottom = (solved_expo - addone); 
		var ready_divide = (solve_top / solve_bottom);
		var result_maker = (ready_divide * minus);
  	var currency = '$';
    

    $("#process").click(function(){
    
    $('#amount').text("$" + result_maker);
    
    });
    
});