JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="input1">
<p>+</p>
<input type="text" id="input2">
<button onclick="Add()" >Get Value</button>
<input type="text" id="answer">
JavaScript
var x;
var y;
function Add()
{
x = document.getElementById("input1").value;
y = document.getElementById("input2").value;
document.getElementById("answer").value = (+x) + (+y)
}