The bridge into algebra: negative numbers, order of operations, variables, one- and two-step equations, ratios, and the coordinate plane.
Free to start · adaptive placement finds your level · reviews timed to your own forgetting.
Every idea is taught with motivation and a worked example before the drills, and an FSRS spaced-repetition engine schedules each review for the day its model predicts you would forget it. A short placement check finds what you already know, so you start Pre-Algebra exactly where it's useful.