1A2B — Bulls & Cows
Daily logic deduction game
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Remember playing this with a pencil in the back of class? Each of you hides a secret number, trading guesses turn by turn — first to crack the other's code wins. That game now lives in your pocket.
The rules take 30 seconds: A = right digit, right spot; B = right digit, wrong spot. Use those two clues to crack the secret number in as few guesses as you can. Simple rules, pure deduction, minutes a round.
— DAILY CHALLENGE
One puzzle a day, the same for everyone worldwide. Build your streak and share your result with friends.
— PLAY THE SAME PUZZLE TOGETHER
Share a game code or QR with friends and everyone gets the same secret number. Deduce on your own, then compare who cracked it in fewer guesses. Great for parties, classrooms and group chats.
— 3 TO 10 DIGITS
Start easy with 3 digits or push your limits at 10. From casual to hardcore.
— PENCIL & PAPER TOOLS, BUILT IN
The best part of 1A2B has always been scribbling notes while you deduce — so we built it in:
• Digit marks: one tap crosses out digits you've ruled out, or circles the ones you know are in
• Position notes: jot candidate digits for every slot and narrow the answer down step by step
• Notes save automatically with each game — leave and pick up your deduction right where you were
— AND MORE
• Full guess history — see every step of your deduction
• Stats and win rate to track your progress
• Hand-drawn notebook feel, like deducing on real paper
• Fully playable offline — commutes, queues, bedtime
Ready? Today's number is waiting.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
• New: play the same puzzle together
• New home screen with a “Continue” list for your games in progress
• Livelier win animation and many small polish fixes
The developer, Yu Te Lu, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Location
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Yu Te Lu
- Size
- 24.1 MB
- Category
- Puzzle
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 40 more
- English, Bengali, Catalan, Croatian, Czech, Danish, Dutch, Finnish, French, German, Greek, Gujarati, Hindi, Hungarian, Indonesian, Italian, Japanese, Kannada, Korean, Malay, Malayalam, Marathi, Norwegian Bokmål, Oriya, Polish, Portuguese, Punjabi, Romanian, Russian, Simplified Chinese, Slovak, Slovenian, Spanish, Swedish, Tamil, Telugu, Thai, Traditional Chinese, Turkish, Ukrainian, Vietnamese
- Age Rating
13+
- 13+
- Contains
Advertising
- In-App Purchases
Yes
- 1A2B Pure $4.99
- Copyright
- © 2026 Yu Te Lu