ProofQuest

Learn to prove things the way mathematicians do — one justified step at a time. Meet the guides who each teach one proof technique, then build proofs yourself.

Level 1

For grown-ups — progress report →A private, on-device snapshot mapped to the skill areas practiced. Export a CSV or print — nothing leaves this device.

Build a proof

Two hands-on reasoning surfaces — the same skills as the iOS app, rebuilt for the browser.

Proof Builder Tap the proof steps in the right order so each one follows from the last. · 16 proofs Counterexample Hunt Find the one case that disproves a claim that looks true. · 6 puzzles

More ways to reason

New proof modalities built for the web first — each one a different way mathematicians justify a claim.

Construction Proof · new Recreate a compass-and-straightedge construction step by step, then see why it works. Two-Column Proof · new Fill in the reason that justifies each statement — the classic school-geometry format. Knights & Knaves · new Knights tell the truth, knaves lie. From what each says, deduce who is which. Induction Dominoes · new Sort the base case, hypothesis, and step — then topple the whole chain. 🌉 Bridge Walk · new The puzzle Euler solved in 1736 — can you cross every bridge exactly once? Predict it from the odd-junction rule, then trace the path to prove it.

Practice the concepts

16 kits from logical-thinking basics up to advanced synthesis — a short round of questions with a hint whenever you get stuck. Your progress stays on this device.

Play together · new on the web

Proof Duel — a head-to-head kit round for 2–4 players. Take turns on one device, or join a friend in an online room by code. Highest first-try score wins; no chat, no accounts.

⚔️ Start a Proof Duel →

Mixed practice · new on the web

Shuffles questions across the kits you've learned and brings them back when they're ready to review — a calmer way to keep old skills fresh. On-device only; practice a couple of kits first.

🔀 Start Mixed practice →