add.js

/*
this is a work around adding numbers and taking care of those that are floats
for e.g
function add(x, y){
  return x + y;
}
add(0.3, 0.1); this will not equal to 0.4 for floats are treated differently see the below link
http://stackoverflow.com/questions/588004/is-floating-point-math-broken
*/
function add(a, b, precision) {
    var x = Math.pow(10, precision || 2);
    return (Math.round(a * x) + Math.round(b * x)) / x;
}