The middle-school contest on-ramp: clever counting, divisibility tricks, rate and geometry puzzles, probability, and the pigeonhole idea — the toolkit before AMC 10/12.
Free to start · adaptive placement finds your level · reviews timed so it stays learned.
Every idea is taught with motivation and a worked example before the drills, and an FSRS spaced-repetition engine schedules each review for the moment just before you'd forget it. A short placement check finds what you already know, so you start AMC 8 & MATHCOUNTS exactly where it's useful.