One of the most simple yet useful tools used by a Certified Public Accountant (CPA) and Certified Internal Auditor (CIA) is the calculator. As an internal auditor, part of my job involves certifying returns or funding requests to our parent Government agency on a periodic basis. There are also research grants funding some of our Centres of Innovation technology development efforts and most grant  agencies require the respective grantees internal auditor to certify that the monies have been spent in accordance to the provisions of the funding agreement.