I understand the reasoning that Mr. Sid and you follow, but I hasten to point out the convinience that weighing provides. Besides the extra precision, you are already supplied with a precise average weight on the bag. To count, you must do repeated trials of both bag and quarter-turny-thingy. To weigh, you need only do repeated trials of the quarter-turny-thingy. So my way is cheaper, no matter what some sadistic math teachers may say!