Common procedures that auditors perform are footing and cross-footing. Footing is the process of adding a column of numbers, and cross-footing is the process of adding a row of numbers. Footing can easily be done by clicking on the Control Total button located on the right of the screen and selecting which column you would like to total. Cross-footing, on the other hand, is not as easy. In the Roger Company Shipping file build an expression to determine if, in any given record, the Subtotal field and the Tax field do not add up to an amount equal to the Invoice_total field. Include the expression you used in your answer. How many cases where the Subtotal field added to the Tax field doesn’t equal the Invoice_total field?