Prime Hunter
A grid of numbers appears and you race the clock tapping only the primes. A wrong tap shakes the tile, and when time's up a full sieve reveal highlights every prime you missed.
Built by the AbraCalc team
How to play
- Set the highest number for the grid and how many seconds you'll have, then tap Start Hunt.
- Tap only the numbers you believe are prime — a correct tap locks in, a wrong one shakes.
- Watch the found-count and time-left counters to track your progress against the clock.
- Clear every prime for a confetti win, or let time run out to see the full sieve reveal.
Set your highest number and a countdown, then tap Start Hunt to fill the grid with every number from 2 up to your chosen max. Your job is to tap only the primes before time runs out — a correct tap locks in and dims, while tapping a composite number by mistake shakes the tile so you know instantly without losing your place. The scoreboard above the grid tracks how many primes you've found out of the true total, so you always know how close you are. Clear every prime before the clock hits zero for a confetti finish, or run out of time and watch the full sieve reveal, which highlights every prime in the grid so you can see exactly which ones you missed. It's built for quick repeated rounds of prime recognition practice, from a starter grid up to two hundred.
Frequently asked questions
- Is 1 counted as a prime number in this game?
- No. The grid starts at 2 and 1 is never included or treated as prime, matching the standard mathematical definition where prime numbers must be greater than 1.
- What happens when I tap a composite number like 49 by mistake?
- The tile shakes to show it was wrong and stays on the board so you can try again — 49 is a good example since it's the square of the prime 7, which makes it composite, not prime.
- What does the sieve reveal show at the end of a round?
- When time runs out or you clear the grid, every prime tile highlights in teal and every composite tile dims, so you can see the complete, correct answer key at a glance.