AMC 10A and AMC 10B are two separate papers administered by the MAA roughly two weeks apart, each year. The content and difficulty are comparable — neither is officially "easier" — and a student may sit both, with the better of the two scores counting toward AIME qualification. Most students aiming seriously for AIME attempt both if the school schedule allows.
What Actually Differs Between 10A and 10B
The two papers are written independently and cover the same syllabus at a comparable difficulty level, though the specific problems and their relative difficulty within each paper naturally vary year to year, as with any two independently-set exams. Neither has a structural advantage — the difference students notice year to year is usually about the specific problem set, not a systematic gap between A and B.
Why Taking Both Makes Sense
- Since the better score counts toward AIME qualification, sitting both effectively gives two attempts at clearing the cutoff in the same year.
- A student who has an off day on one paper — a careless error, unfamiliar problem style — gets a genuine second chance two weeks later.
- The two-week gap is enough time for a focused review of mistakes from the first attempt, without losing preparation momentum.
When Taking Only One Makes Sense
If school commitments, travel, or test-center availability make sitting both genuinely difficult, taking one seriously-prepared attempt is far better than two rushed ones. The value of the second attempt comes from actually being ready for it, not from simply registering for both.