JSFiddle - React, Tailwind, and code Playground

HTML

<form action="" id="myForm">
  <input name="inp13" type="number">
  <input name="inp14" type="number">
</form>

<pre class="div-out7"></pre>

JavaScript

const form = document.getElementById('myForm');
const out7 = document.querySelector('.div-out7');
form.addEventListener('input', updateOut7);

function updateOut7(evt) {
  const a = parseInt(form.inp13.value) || 0;
  const b = parseInt(form.inp14.value, 10) || 0;
  out7.textContent =  a + b;
}