index.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <h1>Loading math.js</h1>
  <script src="https://cdn.jsdelivr.net/npm/lodash@4.17.15/lodash.min.js"
    integrity="sha256-VeNaFBVDhoX3H+gJ37DpT/nTuZTdjYro9yBruHjVmoQ=" crossorigin="anonymous"></script>
  <script src="./build/index.umd.js"></script>
  <script>
    const { add, subtract, multiply, divide } = window.math;
    const addExample = add(1, 2, 3);
    const subtractExample = subtract(10, 5);
    const multiplyExample = multiply(1, 2, 3);
    const divideExample = divide(10, 5);

    // eslint-disable-next-line no-console
    console.log({
      addExample,
      subtractExample,
      multiplyExample,
      divideExample,
    });
  </script>
</body>

</html>