keyUp Example

HTML

<script src="https://code.jquery.com/jquery-2.2.0.min.js"></script>
<form id="form" class="green" method="post">
    <div class="element-number column1">
        <label for="avanti-testa" class="title">
                <span class="titolo-riga required">Number1</span>
                <input id="firstId" class="small" type="number" min="0" max="100" name="number1" required="required" value="0" />
        </label>
    </div>
    <div class="element-number column1">
        <label for="avanti-testa" class="title">
                <span class="titolo-riga required">Number2</span>
            <input id="secondID" class="small" type="number" min="0" max="100" name="number1" required="required" value="0" />
        </label>
    </div> 
    <div id="total">
    <!--placing the total amount here-->
    </div>

JavaScript

$(function(){
//val for firstid
$("#firstId").keyup(function() {
//val of firstId
var total = parseInt($(this).val()) + parseInt($("#secondID").val());
console.log(total);
$("#total").empty().append(total);
});

//for keyup for second
$("#secondID").keyup(function() {
var total = parseInt($(this).val()) + parseInt($("#firstId").val());
console.log(total);
$("#total").empty().append(total);
});

})