Calculated Object

It would be very helpful if there was a type of object (i.e. a sticky) that performed a basic math operations(addition, subtraction, multiplication) against other selected stickies. Selection could work similarly to voting where you could grab the cards in range, select an operation, and create an object like a sticky that will give the result. It can even adjust as the numbers adjust. If an aggregate object is removed, it recalculates without that object. If a invalid character is entered, it informs the user the operation is no longer possible.