Math Grabber
Math Grabber allows you to perform mathematical calculations on numerical text appearing anywhere in a QuarkXPress document
To use Math Grabber click on the Math Grabber tool, drag a marquee around the price column you wish to change, enter the discount and click OK. Math Grabber scans the selected area, calculates the new amounts, and inserts the resulting values automatically.
The Copy Grabber XTension is part of the cost saving Grabber Bundle, wich xou can find here