A complete study library. Not just a question bank.

Concept lessons

The big idea for every concept, the trick to actually understanding it, and the traps that catch people out. Authored and reviewed — never AI-slop.

1,400+ lessons

Explainer videos

A short video for the concept behind almost every lesson, with a transcript beside it so you can read instead of watch.

1,500+ videos

Worked examples

Full solutions revealed one step at a time, at your pace — and they fade out as you get stronger, so you finish them yourself.

1,100+ examples

Visual summaries

Diagrams, graphs and labelled figures drawn from the real numbers — so what you see is exactly what the concept does.

1,400+ lessons

Flashcards

A deck for every unit, scheduled by the same forgetting model that times your reviews — so cards come back exactly when you are about to lose them.

190+ decks

Concept maps

Every concept in a unit on one page, grouped and joined by the relationships between them — the shape of the topic, not a list.

Study guides

A whole unit condensed onto a printable page — key insight per concept, the traps, and the terms worth knowing.

Games

Crosswords, match-ups and put-it-in-order rounds built from the unit's own vocabulary and steps. Nothing invented for the sake of a game.

450+ rounds