I see the argument like this:

We are predestined with a role that we are to play in this life. What we do with it is entirely up to us.

The predestined part is what role you'll end up fulfilling in society (numerology helps you discover that, as I used it to discover my true role), and what one does with that role is completely up to them, as long as it isn't unethical, sinful or otherwise damaging to other people.