JSFiddle - React, Tailwind, and code Playground

JavaScript

var column_width = 30;
var number_of_columns = 13;
var width_of_gutters = 10;
var number_of_gutters = 12;

var result = ((column_width * number_of_columns) + (width_of_gutters * number_of_gutters));

document.write('<a target="blank" href="http://dummyimage.com/' + result  + '">' + result + '</a>');