R3CK0N

Free mental math trainer: timed practice, no signup

R3CK0N is a free mental math practice site that runs in your browser on any phone or computer. Pick an operation and a difficulty, answer against the clock, and get scored on speed, accuracy and consistency. No signup, no ads, nothing to install: your scores are saved on your device, and an account is optional if you want them to follow you.

Modes

  • Math — timed addition, subtraction, multiplication and division at three difficulties, or a custom blend. A Zetamac-style sprint is one preset away.
  • Secret — drills for every technique in Secrets of Mental Math: multiplying by 11, squaring, two-digit multiplication, square roots, day-of-the-week and more.
  • Zen — a numpad typing test: type random five-digit strings and get your keys per second.
  • Flashcards — spaced-repetition decks with FSRS scheduling, or import your Anki decks.
  • Quant Prep — practice for quant trading interviews: a timed trading sprint, an 80 in 8 practice test (80 questions, 8 minutes), probability questions and a market-making game.
  • GRE Prep — GRE-style Quant and Verbal practice questions with explanations, and timed sections.
  • Daily Challenge — the same twenty problems for everyone, once a day.
  • Arena — head-to-head duels with a ranked ladder.
  • Arcade — over 40 quick math games like Survival, Sudoku, 2048, Number Snake and Math Bingo, each with its own best score.

Train · Prep · Compete · Arcade

No ads, no paywall, no account required. JavaScript is needed to play.

Frequently asked questions

What is R3CK0N?

R3CK0N is a free mental math trainer that runs in the browser. It gives you timed arithmetic drills, drills for the techniques in Secrets of Mental Math, a numpad typing test, a daily challenge, spaced-repetition flashcards, quant interview practice and head-to-head duels, and scores every run on speed, accuracy and consistency.

Is R3CK0N free?

Yes. Every drill, mode and game is free, with no ads and no paywall. An optional membership adds perks such as a profile badge, but nothing you need in order to train.

Do I need an account to practise?

No. You can start a drill straight away. Signing in is optional: it syncs your history across devices, puts you on the leaderboards and enables ranked duels.

Does it work on a phone?

Yes. R3CK0N runs in any modern browser on a phone, tablet or computer, and can be added to the home screen like an app. There is nothing to install.

What does it practise?

Addition, subtraction, multiplication and division against the clock at three difficulties or a custom blend; techniques such as multiplying by 11, squaring and two-digit multiplication; times tables one at a time; percentages, fractions and other GRE-style quant skills; and the timed arithmetic tests used in trading interviews.

How is a run scored?

Every run records problems per minute, accuracy and consistency, and the time taken on each problem, so you can see which facts are slowing you down. Your history is kept, in the browser or synced to your account, so progress shows over weeks.

Is R3CK0N a Zetamac alternative?

Yes. Sprint mode is the same two-minute mixed-operation drill with the same default number ranges, and it adds per-problem timing, a saved score history, technique drills, a daily challenge and duels.

Who is it for?

Anyone who wants to get faster at arithmetic: students keeping their mental math sharp, people preparing for GRE, GMAT or SAT quant sections, candidates for quant trading interviews, and anyone who enjoys a timed challenge.

Guides