Tukuk-OSMath — Fast and Faithful
Drill your number sense, keep the formulas, meet the stories
Maths is a muscle: quick daily drills build the number sense that makes everything else easier. Use the sprint trainer below for two minutes a day, keep the formula sheet for reference, and read the stories to see why the numbers matter. Pair with the science explainers for the physics that uses these tools.
Mental-math sprint — 60 seconds
Pick a level, press Start, and answer as many as you can before the clock runs out. Every problem is generated fresh in your browser.
The formula sheet
| Thing | Formula |
|---|---|
| Circle | C = 2πr · A = πr² |
| Rectangle | Perimeter = 2(l + w) · Area = l × w |
| Triangle area | A = ½ × base × height |
| Pythagoras | a² + b² = c² (right triangles) |
| Volume of a box | V = l × w × h |
| Sphere | V = ⁄₃ πr³ · A = 4πr² |
| Quadratic formula | x = (−b ± √(b² − 4ac)) / 2a |
| Simple interest | I = P × r × t |
| Percentage change | (new − old) / old × 100% |
| Average (mean) | sum of values ÷ number of values |
| Speed | speed = distance ÷ time |
| Density | density = mass ÷ volume |
Numbers with a story
• Zero became a number in India by the 7th century — before that, "nothing" was not something you could count with.
• A shuffled deck of 52 cards has about 8×1067 possible orders — more than the seconds since the Big Bang, so your shuffle has almost certainly never happened before.
• The Babylonians knew the Pythagorean relationship over a thousand years before Pythagoras; a clay tablet (Plimpton 322, c. 1800 BC) lists correct triples.
• Every map ever drawn needs at most four colours — the Four Colour Theorem, proven with a computer in 1976.