About NumDojo
Where ancient wisdom meets modern learning
NumDojo brings three speed-calculation systems into one lesson library. Learners can work through examples, solve practice problems, save progress, and return to scheduled review.
Key facts
- Audience: learners roughly ages 8 to 18, plus adult learners
- Methods: Vedic Mathematics, Trachtenberg System, Soroban / mental Anzan
- Curriculum: ~180 structured lessons with practice problems
- Retention: SM-2 style spaced-repetition review queue
- Battle launch: timed computer practice with no rating or competitive XP
- Child privacy: public registration begins at 13 with high-privacy minor defaults
- Offer: Free plan plus a £14.99 monthly Pro pilot for invited UK adults
- Founder: Velislav Tihomirov Tsvetanov (0xDarkArt)
Vedic Mathematics
Pattern-based techniques organised around 16 sutras, with lessons from multiplication to square roots.
Trachtenberg System
A systematic method for rapid mental multiplication without memorizing tables.
Soroban
Japanese abacus lessons covering bead values, complements, and mental Anzan practice.
Battle Practice
Timed first-to-three matches against the computer, with no rating change or competitive XP.
Our Approach
Every lesson in NumDojo follows a structured path: learn the technique, watch worked examples, practice with guided problems, then challenge yourself in timed drills and computer practice. Correct practice answers schedule a longer review interval, while missed answers return sooner. XP, levels, badges, and streaks record activity inside the app.
Not sure which method to start with? Read our comparison: Vedic vs Trachtenberg vs Soroban.
Current Launch Scope
The controlled launch is for individual accounts. NumDojo is not onboarding paid family, teacher, school, classroom, or managed-workspace customers yet.
Who built NumDojo
NumDojo is built and maintained by Velislav Tihomirov Tsvetanov, who also works under the name 0xDarkArt, an independent developer specializing in full-stack applications, Web3 products, and smart contract security. The platform was shipped as a production SaaS: Next.js frontend, Node.js API, PostgreSQL, Redis, Socket.io Battle practice, and a Stripe subscription integration. Public paid checkout is not open during the controlled launch.
Learn more about the build on the NumDojo case study, or visit www.0xdarkart.xyz for app/dApp development and audit services.
About NumDojo FAQ
What is NumDojo?
NumDojo is a speed-math learning platform with lessons in Vedic Mathematics, the Trachtenberg System, and Soroban. The current launch includes saved progress, scheduled review, and timed computer practice in Battle mode.
Is NumDojo free?
Yes. The Free plan includes 42 foundation lessons, 20 practice problems per day, saved progress, scheduled review, and computer Battle practice. The first paid offer is a £14.99 monthly Pro pilot for invited UK adults aged 18 or over.
Is NumDojo safe for children under 13?
Children under 13 cannot self-register, and managed-account onboarding is not open during the current launch. Optional analytics and free-text messaging are disabled for signed-in minors. Details are in the Children's Privacy Notice.
Who built NumDojo?
NumDojo was designed and engineered by Velislav Tihomirov Tsvetanov, who also works under the name 0xDarkArt.