Since each pencil set is made with exactly 15 pencils, and the shipment is comprised of 634 pencils, we have to divide 634 (total) by 15 (number of pencils in each set). In return we get 42.26 repeating, but since a set cannot contain only a fraction of pencils as a normal one, the store can only make a maximum of 42 sets (with some left over). Therefore, the greatest number of pencil sets the store can sell is 42.
