Streak · 7 days+185 XP
7-Day Prime Puzzle Streak
Solve one prime-number puzzle or factor one number each day. Check in with your answer.
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Science · Facts & stats · iChallenge network
The Prime Challenge
Daily facts and stats about prime numbers and number theory, plus real challenges to put them to work.
Today's 3 challenges
The Fundamental Theorem of Arithmetic says every integer above 1 has what?
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Level1Rookie
XPPlay a round to earn XP
Streak0days
LeagueBronzeweekly
Daily #32Resets at midnight UTC
Today's round
- 5 questions
- 20s each
- 0 played today
One ranked attempt per day. Practice as much as you like.
Challenges
Join one, log your days or post your proof. Finishing earns XP and the Finisher badge.
Proof+250 XP
Sieve of Eratosthenes
Use the sieve method on paper to find all primes up to 100. Post a photo link.
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Proof+250 XP
Prime Factor Tree
Draw factor trees for five numbers of your choice. Post a photo link.
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Streak · 14 days+220 XP
14-Day Math Minute
Spend ten minutes a day on math practice. Check in once a day.
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By the numbers
Live counts from PrimeChallenge.com. All arena stats →
Facts in the pack12
Visitors, 30 days28
Leaderboard
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Badges
Earned on any arena, shown on your profile everywhere.
First RoundFinish your first daily round.
FlawlessAnswer every question in a round correctly.
LightningA perfect round in under 25 seconds.
On a RollPlay 3 days in a row.
Week WarriorPlay 7 days in a row.
UnbreakablePlay 30 days in a row.
ExplorerPlay daily rounds in 5 different arenas.
GlobetrotterPlay daily rounds in 25 different arenas.
PolymathPlay daily rounds in 5 different topics.
In the ArenaJoin your first challenge.
FinisherComplete a challenge.
RecruiterInvite a friend who finishes a round.
CaptainInvite 5 friends who finish a round.
PodiumFinish a day in an arena's top 3.
ChallengerReach level 10.
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Add your email to keep your level, streak and badges if you switch devices, and carry them to every iChallenge arena. One email when you save; no spam.
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- Pick the challenge and the prize
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- You get finisher and engagement numbers after it closes
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Questions
How does scoring work?
100 points per correct answer, up to 50 more for speed, a combo multiplier for answers in a row, and a bonus for a perfect round.
When do new questions drop?
Fresh rounds rotate continuously from the topic bank.
How does the daily round work?
Everyone on this arena gets the same five questions each day, from easy to hard. You get one ranked attempt; practice rounds are unlimited.
How is my score calculated?
100 points per correct answer, up to 50 more for answering quickly, a combo multiplier for answers in a row, and 150 bonus points for a perfect round.
Is it free?
Yes. Playing, streaks, badges and leaderboards are free. Some challenges carry a sponsor-funded prize; the challenge card shows it when one is funded.