Mental math practice that measures your speed
Short answer: the mental math practice that works is short, daily, timed, and aimed at the facts that are slowest for you. R3CK0N gives you that in the browser for free, with no account: timed drills for all four operations, a time for every problem, and a history that shows whether you are getting faster.
Most mental math practice fails for one reason: you can't tell whether it's working. A timed drill fixes that. Every run gives you a number, and the number either moves or it doesn't.
Start a drill — free, no sign-upHow to practise mental arithmetic
Mental calculation is a skill like touch typing: it improves with short, frequent, measured sessions. A few principles do most of the work:
- Short sessions, often. Sixty seconds a day beats an hour once a week. A daily streak is worth protecting.
- Measure speed and accuracy together. Speed without accuracy is guessing. Track correct answers per minute, not attempts.
- Find your slow problems. One problem that takes four times longer than the rest is usually a missing technique, not a lack of practice.
- Raise the difficulty when it gets easy. If your accuracy is consistently high, move up a level rather than grinding the same range.
What the drills cover
R3CK0N's Math mode drills the four operations at three difficulties. Division problems always have whole-number answers.
| Operation | Easy | Medium | Hard |
|---|---|---|---|
| Addition | 2–99 | 10–999 | 100–9,999 |
| Subtraction | 2–99 | 10–999 | 100–9,999 |
| Multiplication | 2–12 (times tables) | 2–99 | 11–99 × 11–99 |
| Division | ÷ 2–9 | ÷ 2–12 | ÷ 3–25 |
You can run against the clock (15 to 120 seconds) or over a fixed count (10 to 100 problems), and a Custom mode blends the operations with whatever weighting you want.
Quick techniques for each operation
Addition: work left to right
School teaches right to left because it suits paper. In your head, start with the biggest place value: 47 + 38 is 70 + 15 = 85. You know the rough answer immediately and refine it.
Subtraction: round, then correct
83 − 29 is awkward; 83 − 30 + 1 = 54 is not. Round the number you're subtracting to a friendly value, then give back the difference.
Multiplication: split one factor
47 × 8 is 40 × 8 + 7 × 8 = 320 + 56 = 376. For two-digit by two-digit, see the guide to multiplying two-digit numbers in your head.
Division: think in multiplication
144 ÷ 12 asks "what times 12 makes 144?" Solid times tables make division nearly free.
How your speed is scored
PPM (problems per minute) is correct answers normalised to 60 seconds. Raw PPM counts every answer, right or wrong. Accuracy is the share you got right first time. After each run you see a bar for every problem — height is time taken, colour is right or wrong — so slow spots are obvious.
Frequently asked questions
Is it free?
Yes. No ads, no paywall, and no account needed. Your history stays in your browser unless you choose to sign in and sync it.
What's a good mental math speed?
It depends heavily on difficulty, so the useful comparison is with yourself. Watch your PPM on one setting over a few weeks.
Does it work on a phone?
Yes. It runs in any modern browser and can be installed to your home screen.
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