Well this was a rather debated issue i believe, for example in our exam last year for class of 2003, what happened was, Hexadecimal conversion was definately taught in year 11 however, i don't think many people remembered or just didn't focus on it, primarily because it's touched up more in the Option Topi: Developer's view of hardware. What happened was many people thought it was rather unfair, since the people doing the other topic, i.e. Evolution of programming languages, was rather disadvantaged since they wouldn't of revised the 3 basic computer number systems.