<div class="a">
<input type="text" value="1">
<input type="text" value="33">
<input type="text" value="55">
<input type="text" value="d">
</div>
<div class="out"></div>
const a = document.querySelector('.a');
const out = document.querySelector('.out');
out.textContent = a.childNodes.reduce((acc, x) => { return acc + x.value }, '');