Sixth Term Examination Papers
Exam papers are set in all major A-Levels by Cambridge University. Academic offers of places ocasionaly include a requirement of certain grades in one or more STEP papers, though more often candidates do STEP papers either as a backup because they think they are going to miss their required A-Level grades, or because they want to reapply to Cambridge after they have their results. Step papers are graded fail, 3 (satisfactory), 2 (good), 1 (very good), S (outstanding).
STEP grades are almost always part of the academic requirement for entry into the Maths Tripos. Maths STEP is very hard, a fact I know all too well due to the fact I fucked mine up, and thus didn't get my Cambridge offer. Ooops