Speed quiz
Click only the primes
The numbers 1 to 100 are on the board. Click all 25 primes in any order. Click anything else and the game is over.
- Format
- Click the grid
- Items
- 25 to click
- Limit
- 2:00
- Level
- Medium
- Checked
- 2026.10.02
- To find
- 25
- Time limit
- 2:00
- Minefield
- One wrong click ends it
- Click every valid item, in any order.
- Decoys look plausible. Read carefully.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Click every prime number, and nothing else. The grid appears when you start.
About this quiz
A prime has exactly two divisors: 1 and itself. There are 25 primes below 100, and 1 is not one of them.
- 2 is the only even prime.
- 1 is not prime, because it has only one divisor.
- 91 looks prime but is 7 times 13.
- The largest prime below 100 is 97.
More quizzes like this
| No. | Quiz | Section | Format | Items | Added |
|---|---|---|---|---|---|
| 01 | Click the odd numbers Click every odd number from 1 to 60, and nothing else. There are 30 of them, and one click on an even number ends the game. Speed / Click the grid / 30 to click | Speed | Click the grid | 30 | 2026.10.03 |
| 02 | Click 1 to 100 Click the numbers from 1 to 100 in order. The grid reshuffles after every correct click, and one wrong click ends the game. Speed / Click the grid / 100 to click | Speed | Click the grid | 100 | 2026.10.02 |
| 03 | Anything but 7 Click every number from 1 to 70 that has nothing to do with 7: not a multiple of 7 and no 7 among its digits. 54 are safe. Speed / Click the grid / 54 to click | Speed | Click the grid | 54 | 2026.10.03 |