Proof+250 XP
Parity Grid Puzzle
Make a 5x5 grid of 0s and 1s with a parity bit on each row and column, have a friend flip one bit, find it and post a write-up.
SponsorseCorp.comSavingTheWorld.orgVentureOS.com
Be the first to join
Tech · Facts & stats · iChallenge network
The BCH Challenge
Daily facts and stats about error-correcting codes, plus real challenges to put them to work.
Today's 3 challenges
A code whose codewords differ in at least 3 positions can correct how many bit errors per codeword?
You went
Level1Rookie
XPPlay a round to earn XP
Streak0days
LeagueBronzeweekly
Daily #41Resets 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.
Streak · 7 days+185 XP
7-Day Binary Word Streak
Each day, write one short word in binary using ASCII codes and check it with a chart. Check in daily.
SponsorseCorp.comSavingTheWorld.orgVentureOS.com
Be the first to join
Proof+250 XP
Check Digit Detective
Verify the ISBN-13 check digit on three books by hand and post your working as a short write-up.
SponsorseCorp.comSavingTheWorld.orgVentureOS.com
Be the first to join
By the numbers
Live counts from BCHChallenge.com. All arena stats →
Facts in the pack12
Visitors, 30 days55
Challenge joins4
Leaderboard
- Loading…
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.
Profile SavedSave your progress with an email.
Save your progress
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.
Put a prize on a challenge
Fund a prize on BCHChallenge.com and your brand sits on the challenge card, the leaderboard and every finisher's share. Prizes only appear once they're funded, so players can trust what they see.
- Pick the challenge and the prize
- We review entries before a funded prize is awarded
- You get finisher and engagement numbers after it closes
Current sponsors
Questions
Is this financial advice?
No — knowledge games only. Nothing here is financial advice.
Are there prizes?
Only when a sponsor funds a prize. Funded prizes and their rules are shown on the challenge card; otherwise you play for rank and badges.
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.