JSFiddle - React, Tailwind, and code Playground
by Joshua Dwire
HTML
<input id="a" type="text"/>
<input id="b" type="text"/>
<button onclick="calculate()">Calculate</button>
<input type="text" id="c"/>
JavaScript
window.calculate=function(){
var aVal = parseFloat('0.'+document.getElementById('a').value,10)
var bVal = parseFloat('0.'+document.getElementById('b').value,10)
var cval = aVal+((bVal-aVal)/2);
document.getElementById('c').value=cval;
}