About 30s Math

30s Math is a free browser game about mental arithmetic under pressure. Every run lasts 30 seconds, every question has four choices, and a single wrong answer ends the run immediately. There is nothing to install and no account to create.

Why we built it

Most arithmetic drills reward patience: you can take as long as you like, and a mistake costs nothing. We wanted the opposite — a short, honest test of how quickly you can read an expression, estimate the result, and commit to an answer. Thirty seconds is long enough to find a rhythm and short enough to try again right away.

How the game works

• Easy — small numbers, a single operation.
• Normal — two-step expressions with mixed values.
• Hard — larger values and mixed operations.
• Expert — multi-step expressions that mix everything together.

Questions are generated in your browser at the moment they appear, so no two runs are identical. The distractor options are built close to the correct answer, which means guessing rarely works — you have to actually do the arithmetic.

The leaderboard

Submitting a score is optional. If you choose to submit one, you pick a display name and complete a bot check, and the score is stored so it can appear on the daily and all-time boards. Your personal best is also kept locally in your browser so you can track your own progress without submitting anything.

Who maintains the site

30s Math is built and maintained by Jaegyeom Kim, an independent developer. The game, its artwork, and the text on this site are original work. We fix reported issues and ship small improvements regularly.

You can find more about the developer on the CMaybe blog or on GitHub.

Questions, bug reports, and feedback are welcome — see the Contact page.