Science quiz
Prime numbers under 100
Twenty five primes hide below 100. Type them in any order; press Enter after 2, 3, 5 and 7, which also start longer primes.
- Format
- Type them all
- Items
- 25 answers
- Limit
- 3:00
- Level
- Medium
- Checked
- 2026.10.03
- Answers
- 25
- Time limit
- 3:00
- Order
- Any order
- Matching
- Case and accents ignored
- Type an answer; it files itself the moment it matches.
- One answer can fill several slots.
- Give up at any time to see what you missed.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Type every prime number under 100.
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About this quiz
A prime number has exactly two divisors, 1 and itself. Below 100 there are 25 of them, and they thin out as the numbers grow.
- 2 is the only even prime.
- 1 is not prime, because it has only one divisor.
- There are eight pairs of twin primes under 100, such as 11 and 13 or 71 and 73.
- 91 and 87 look prime but are 7 times 13 and 3 times 29.
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