Thanks, Tory. Is it possible for a student to take those exams and score a level different than "A?" Is there a level "B" or something lower? If so, how many levels are there, and what are they designated?
It seems like a rational system.
I haven't explained it well (it's changed since my day of 'O' and 'A' Levels). Previously, there were 3 exam levels: CSE (Certificate of Secondary Education) was the lowest rank -- a minimum number of these would be something like the basic American High School Diploma. Typically, most students additional took some 'O' (Ordinary) Level exams; completion of 'O' Levels marked the end of secondary education for a number of pupils, though if you were aiming at university entrance, you needed to do a further year in school and round of 'A' (Advanced) Level exams. Since my time, the CSE's and O Levels have been combined into the GCSE level (lowest) with new AS and A levels introduced for higher qualifications.
It is probably more rational than I have explained!