Recycling by product massive number of types of plastic, they each carry a resin identification code, and must be sorted before they can be recycled. This can be costly; while metals can be sorted using electromagnets, no such 'easy sorting' capability exists for plastics. In addition to this, while labels do not need to be removed from bottles for recycling, lids are often made from a different kind of non-recyclable plastic. To help in identifying the materials in various plastic items, resin identification code numbers 1-6 have been assigned to six common kinds of recyclable plastic resins, with the number 7 indicating any
Joint Academic Coding System letter can be used twice (if the two subjects are within the same general subject area), such as FF53 for Astronomy and Physics. Coding is done differently for courses such as "Mathematics with Physics", which is not the same as "Mathematics and Physics". The format for such courses is Y1Z9 where: For example, Mathematics with Physics would be represented by G1F3, but Physics with Mathematics would be represented by F3G1. Hence the order in which the two subjects are notated was important historically. Joint Academic Coding System The Joint Academic Coding System (JACS) system is used by the Higher Education