I dispute that economics is the same thing as what the bible calls stewardship.

Yes, economics - the real economics - is science. It has it's own methods and laws. Just like in applied physics or applied physics, though, non-linear problems are not handled so well by the existing models.

There is at least one very highly mathematical in economics - cost analysis. Look up "linear programming" in google. Regardless of whether economics is science, "stewardship" is not.