JSFiddle - React, Tailwind, and code Playground

HTML

<select id="userVal">
    <option value="012">Primary</option>
    <option value="345">Secondary</option>
    <option value="678">Tertiary</option>
</select>
<button id="calculate">Calculate</button>
<br />Primary:
<input type="text" name="resource_012_1" />
<br />Primary:
<input type="text" name="resource_012_2" />
<br />Secondary:
<input type="text" name="resource_345_1" />
<br />Secondary:
<input type="text" name="resource_345_2" />
<br />Tertiary:
<input type="text" name="resource_678_1" />
<br />Tertiary:
<input type="text" name="resource_678_2" />
<br />Total: <span id="total"></span>

JavaScript

jQuery(function ($) {
    var userVal = $('#userVal'),
        calculateBtn = $('#calculate'),
        total = $('#total');

    calculateBtn.on('click', function (evt) {
        evt.preventDefault();
        //var samp = $(thisVal).attr('name');  //user defined name 
        var samp = userVal.val(),
            tot = 0,
            inputs = $('input[name^="resource_' + samp + '_"]');

        inputs.each(function () {
            var v = $(this).val();
            if (v === '') {
                v = 0;
            }
            tot += parseInt(v);
        });
        total.text(tot);
    });

});