All your topic tests, assignmnets, half yearly exams, all count for 50% or your total mark
Then the trail HSC and the main HSC at the end, then add up to the remainder 50%
So its an ongoing process, and yeah....
At the end, you end up getting a mark out of 200 for the course, that mark is then scaled on the dificulty of the course,
Then your top 10 units out of however many your doing, after scaling, is then added up, and put into a list and wherever you are on that ranked order list, is your UAI. Which is the score that gets you into unis.