If all of the dimensions of the shipping box are 1.3 times that of the gift, then the volume of the box is 1.3^3=2.197 times that of the gift. Dividing this by the volume of the box, you get a volume of 2000 cubic centimeters for the volume of the gift. Subtracting this from the volume of the box, you get 2394 cubic centimeters of unused space. Hope this helps!
