JSFiddle - React, Tailwind, and code Playground
HTML
<input id="refundAmount2" value="0.012" />
<input id="refundReceived" value="0.08" />
JavaScript
var refundAmount = parseFloat($('#refundAmount2').val().replace('$',''));
var refundReceived = $('#refundReceived');
var remainderAmount = refundAmount-parseFloat(refundReceived.val().replace('$',''));
alert(parseFloat(0.03).toFixed(2));