Printable code breaker puzzles with answers

Print the puzzles

Printing gives you all 20 puzzles without the answers, and the answer key on a page of its own. On screen, type your answer under a puzzle and press Check, or open the step by step answer.

How the clues work

Every puzzle hides a code with no repeated digits. A code can start with 0. Each clue shows a guess and tells you two things about it: how many of its digits are in the code at all, and how many of those sit in the right place.

• "Exactly 1 digit is correct and in the correct position." One digit of the guess is in the code, in that exact spot. The others aren't in the code.
• "Exactly 1 digit is in the code but in a different position." One digit is in the code, somewhere else. The others aren't in the code.
• "None of these digits is in the code." Cross all of them out. This is usually the best place to start.

Clues with bigger numbers work the same way, just with more digits. Every puzzle here has exactly one code that fits all its clues, and you can always reach it by reasoning, without trying codes at random.

Lock riddles, 3 digits

The kind you've seen on a padlock picture: three digits and a handful of clues. A good warm up.

1. B1 3 digits, 4 clues

   Guess	Clue
   028	None of these digits is in the code.
   941	Exactly 1 digit is in the code but in a different position.
   675	Exactly 2 digits are in the code but in different positions.
   146	Exactly 2 digits are correct and in the correct positions.

   Code:

   Your answer to B1Check
   Answer to B1

   The code is 156. Step by step:

   1. Clue 1 says none of its digits is in the code. 0, 2 and 8 aren't in the code.
   2. Clue 2 has no digit in the right slot. 1 isn't in slot 3; 4 isn't in slot 2; 9 isn't in slot 1.
   3. Clue 3 has no digit in the right slot. 5 isn't in slot 3; 6 isn't in slot 1; 7 isn't in slot 2.
   4. Clue 4 needs 2 digits in the right slot, and only 1 and 6 can still be there. 1 goes in slot 1; 6 goes in slot 3.
   5. 4 has no slot left where it could go. 4 isn't in the code.
   6. 7 has no slot left where it could go. 7 isn't in the code.
   7. Clue 2 has 2 digits that aren't in the code, and only 9 and 4 can still be missing. 9 isn't in the code.
   8. Clue 3 has 1 digit that isn't in the code, and 7 is already that one. 5 is in the code.
   9. The code has 3 digits, and you already know 1, 5 and 6 are in it. 3 isn't in the code.

2. B2 3 digits, 4 clues

   Guess	Clue
   092	Exactly 1 digit is correct and in the correct position.
   172	Exactly 1 digit is in the code but in a different position.
   327	Exactly 2 digits are correct and in the correct positions.
   016	None of these digits is in the code.

   Code:

   Your answer to B2Check
   Answer to B2

   The code is 397. Step by step:

   1. Clue 4 says none of its digits is in the code. 0, 1 and 6 aren't in the code.
   2. Clue 1 has no correct digit in a different slot. 2 isn't in slots 1 or 2; 9 isn't in slots 1 or 3.
   3. Clue 2 has no digit in the right slot. 2 isn't in slot 3; 7 isn't in slot 2.
   4. 2 has no slot left where it could go. 2 isn't in the code.
   5. Clue 1 needs 1 digit in the right slot, and only 9 can still be there. 9 goes in slot 2.
   6. Clue 2 has 2 digits that aren't in the code, and 1 and 2 are already those. 7 is in the code.
   7. Clue 3 needs 2 digits in the right slot, and only 3 and 7 can still be there. 3 goes in slot 1; 7 goes in slot 3.

3. B3 3 digits, 4 clues

   Guess	Clue
   420	Exactly 2 digits are in the code but in different positions.
   539	Exactly 1 digit is in the code but in a different position.
   957	None of these digits is in the code.
   643	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to B3Check
   Answer to B3

   The code is 302. Step by step:

   1. Clue 3 says none of its digits is in the code. 9, 5 and 7 aren't in the code.
   2. Clue 1 has no digit in the right slot. 0 isn't in slot 3; 2 isn't in slot 2; 4 isn't in slot 1.
   3. Clue 2 has no digit in the right slot. 3 isn't in slot 2.
   4. Clue 2 has 2 digits that aren't in the code, and 5 and 9 are already those. 3 is in the code.
   5. Clue 4 has no digit in the right slot. 3 isn't in slot 3; 4 isn't in slot 2; 6 isn't in slot 1.
   6. Clue 4 has 2 digits that aren't in the code, and only 6 and 4 can still be missing. 6 and 4 aren't in the code.
   7. Clue 1 has 1 digit that isn't in the code, and 4 is already that one. 2 and 0 are in the code.
   8. The code has 3 digits, and you already know 0, 2 and 3 are in it. 1 and 8 aren't in the code.
   9. Only 0 can still go in slot 2. 0 goes in slot 2.
   10. Only 2 can still go in slot 3. 2 goes in slot 3.

4. B4 3 digits, 4 clues

   Guess	Clue
   691	Exactly 1 digit is in the code but in a different position.
   670	Exactly 1 digit is in the code but in a different position.
   192	Exactly 2 digits are correct and in the correct positions.
   679	None of these digits is in the code.

   Code:

   Your answer to B4Check
   Answer to B4

   The code is 102. Step by step:

   1. Clue 4 says none of its digits is in the code. 6, 7 and 9 aren't in the code.
   2. Clue 1 has no digit in the right slot. 1 isn't in slot 3.
   3. Clue 1 has 2 digits that aren't in the code, and 6 and 9 are already those. 1 is in the code.
   4. Clue 2 has no digit in the right slot. 0 isn't in slot 3.
   5. Clue 2 has 2 digits that aren't in the code, and 6 and 7 are already those. 0 is in the code.
   6. Clue 3 needs 2 digits in the right slot, and only 1 and 2 can still be there. 1 goes in slot 1; 2 goes in slot 3.
   7. The code has 3 digits, and you already know 0, 1 and 2 are in it. 3, 4, 5 and 8 aren't in the code.

5. B5 3 digits, 4 clues

   Guess	Clue
   184	Exactly 1 digit is correct and in the correct position.
   802	None of these digits is in the code.
   367	Exactly 2 digits are in the code but in different positions.
   137	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to B5Check
   Answer to B5

   The code is 674. Step by step:

   1. Clue 2 says none of its digits is in the code. 8, 0 and 2 aren't in the code.
   2. Clue 1 has no correct digit in a different slot. 1 isn't in slots 2 or 3; 4 isn't in slots 1 or 2.
   3. Clue 3 has no digit in the right slot. 3 isn't in slot 1; 6 isn't in slot 2; 7 isn't in slot 3.
   4. Clue 4 has no digit in the right slot. 1 isn't in slot 1; 3 isn't in slot 2.
   5. 1 has no slot left where it could go. 1 isn't in the code.
   6. Clue 1 needs 1 digit in the right slot, and only 4 can still be there. 4 goes in slot 3.
   7. 3 has no slot left where it could go. 3 isn't in the code.
   8. Clue 3 has 1 digit that isn't in the code, and 3 is already that one. 6 and 7 are in the code.
   9. The code has 3 digits, and you already know 4, 6 and 7 are in it. 5 and 9 aren't in the code.
   10. Only 7 can still go in slot 2. 7 goes in slot 2.

6. B6 3 digits, 5 clues

   Guess	Clue
   038	Exactly 1 digit is correct and in the correct position.
   609	Exactly 1 digit is in the code but in a different position.
   980	Exactly 1 digit is correct and in the correct position.
   201	None of these digits is in the code.
   416	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to B6Check
   Answer to B6

   The code is 934. Step by step:

   1. Clue 4 says none of its digits is in the code. 2, 0 and 1 aren't in the code.
   2. Clue 1 has no correct digit in a different slot. 3 isn't in slots 1 or 3; 8 isn't in slots 1 or 2.
   3. Clue 2 has no digit in the right slot. 6 isn't in slot 1; 9 isn't in slot 3.
   4. Clue 3 needs 1 digit in the right slot, and only 9 can still be there. 9 goes in slot 1.
   5. Clue 2 has 2 digits that aren't in the code, and only 6 and 0 can still be missing. 6 isn't in the code.
   6. Clue 3 has 2 digits that aren't in the code, and only 8 and 0 can still be missing. 8 isn't in the code.
   7. Clue 1 needs 1 digit in the right slot, and only 3 can still be there. 3 goes in slot 2.
   8. Clue 5 has 2 digits that aren't in the code, and 1 and 6 are already those. 4 is in the code.
   9. The code has 3 digits, and you already know 3, 4 and 9 are in it. 5 and 7 aren't in the code.

4 digits

One more digit, and clues where some digits are right and some are only in the code.

1. M1 4 digits, 6 clues

   Guess	Clue
   2490	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   9238	Exactly 2 digits are in the code but in different positions.
   8217	Exactly 1 digit is in the code but in a different position.
   7981	None of these digits is in the code.
   4096	Exactly 1 digit is correct and in the correct position.
   6284	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to M1Check
   Answer to M1

   The code is 2053. Step by step:

   1. Clue 4 says none of its digits is in the code. 7, 9, 8 and 1 aren't in the code.
   2. Clue 2 has no digit in the right slot. 2 isn't in slot 2; 3 isn't in slot 3.
   3. Clue 2 has 2 digits that aren't in the code, and 9 and 8 are already those. 2 and 3 are in the code.
   4. Clue 5 has no correct digit in a different slot. 0 isn't in slots 1, 3 or 4; 4 isn't in slots 2, 3 or 4; 6 isn't in slots 1, 2 or 3.
   5. Clue 1 needs 1 digit in the right slot, and only 2 can still be there. 2 goes in slot 1.
   6. Only 5 can still go in slot 3. 5 goes in slot 3.
   7. 4 has no slot left where it could go. 4 isn't in the code.
   8. Clue 1 has 2 digits that aren't in the code, and 4 and 9 are already those. 0 is in the code.
   9. Clue 5 has 1 digit in the right slot, and 0 is already that one. 6 isn't in slot 4.
   10. Only 3 can still go in slot 4. 3 goes in slot 4.

2. M2 4 digits, 6 clues

   Guess	Clue
   5762	Exactly 1 digit is in the code but in a different position.
   3594	Exactly 1 digit is correct and in the correct position.
   7438	None of these digits is in the code.
   6275	Exactly 1 digit is correct and in the correct position.
   3761	Exactly 1 digit is in the code but in a different position.
   4967	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to M2Check
   Answer to M2

   The code is 1290. Step by step:

   1. Clue 3 says none of its digits is in the code. 7, 4, 3 and 8 aren't in the code.
   2. Clue 1 has no digit in the right slot. 2 isn't in slot 4; 5 isn't in slot 1; 6 isn't in slot 3.
   3. Clue 2 has no correct digit in a different slot. 5 isn't in slots 3 or 4; 9 isn't in slots 1, 2 or 4.
   4. Clue 4 has no correct digit in a different slot. 2 isn't in slots 1 or 3; 5 isn't in slot 2; 6 isn't in slots 2 or 4.
   5. 5 has no slot left where it could go. 5 isn't in the code.
   6. Clue 2 needs 1 digit in the right slot, and only 9 can still be there. 9 goes in slot 3.
   7. Clue 5 has no digit in the right slot. 1 isn't in slot 4.
   8. Only 0 can still go in slot 4. 0 goes in slot 4.
   9. Clue 6 has 3 digits that aren't in the code, and only 4, 6 and 7 can still be missing. 6 isn't in the code.
   10. Only 1 can still go in slot 1. 1 goes in slot 1.
   11. Only 2 can still go in slot 2. 2 goes in slot 2.

3. M3 4 digits, 6 clues

   Guess	Clue
   3862	Exactly 1 digit is correct and in the correct position.
   4165	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   9576	Exactly 1 digit is in the code but in a different position.
   6037	Exactly 1 digit is in the code but in a different position.
   9174	Exactly 1 digit is in the code but in a different position.
   7125	Exactly 1 digit is correct and in the correct position.

   Code:

   Your answer to M3Check
   Answer to M3

   The code is 0845. Step by step:

   1. Clue 1 has no correct digit in a different slot. 2 isn't in slots 1, 2 or 3; 3 isn't in slots 2, 3 or 4; 6 isn't in slots 1, 2 or 4; 8 isn't in slots 1, 3 or 4.
   2. Clue 3 has no digit in the right slot. 5 isn't in slot 2; 7 isn't in slot 3; 9 isn't in slot 1.
   3. Clue 4 has no digit in the right slot. 0 isn't in slot 2; 7 isn't in slot 4.
   4. Clue 5 has no digit in the right slot. 1 isn't in slot 2; 4 isn't in slot 4.
   5. Clue 6 has no correct digit in a different slot. 1 isn't in slots 1, 3 or 4; 2 isn't in slot 4; 5 isn't in slots 1 or 3; 7 isn't in slot 2.
   6. 1 has no slot left where it could go. 1 isn't in the code.
   7. 2 has no slot left where it could go. 2 isn't in the code.
   8. Clue 2 needs 1 correct digit in a different slot, and only 4 can still be that one. 4 is in the code; 4 isn't in slot 1.
   9. Clue 5 has 3 digits that aren't in the code, and only 9, 1 and 7 can still be missing. 9 and 7 aren't in the code.
   10. Clue 6 needs 1 digit in the right slot, and only 5 can still be there. 5 goes in slot 4.
   11. Clue 2 has 1 digit in the right slot, and 5 is already that one. 6 isn't in slot 3.
   12. 6 has no slot left where it could go. 6 isn't in the code.
   13. Suppose 0 goes in slot 3. Then clue 4 can't be true anymore. 0 isn't in slot 3.
   14. Only 4 can still go in slot 3. 4 goes in slot 3.
   15. Only 8 can still go in slot 2. 8 goes in slot 2.
   16. Clue 1 has 1 digit in the right slot, and 8 is already that one. 3 isn't in slot 1.
   17. Only 0 can still go in slot 1. 0 goes in slot 1.

4. M4 4 digits, 6 clues

   Guess	Clue
   9145	Exactly 1 digit is in the code but in a different position.
   5384	Exactly 2 digits are in the code but in different positions.
   1258	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   7634	Exactly 1 digit is correct and in the correct position.
   8763	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   3169	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to M4Check
   Answer to M4

   The code is 8650. Step by step:

   1. Clue 1 has no digit in the right slot. 1 isn't in slot 2; 4 isn't in slot 3; 5 isn't in slot 4; 9 isn't in slot 1.
   2. Clue 2 has no digit in the right slot. 3 isn't in slot 2; 4 isn't in slot 4; 5 isn't in slot 1; 8 isn't in slot 3.
   3. Clue 4 has no correct digit in a different slot. 3 isn't in slots 1 or 4; 4 isn't in slots 1 or 2; 6 isn't in slots 1, 3 or 4; 7 isn't in slots 2, 3 or 4.
   4. 4 has no slot left where it could go. 4 isn't in the code.
   5. Clue 5 needs 1 digit in the right slot, and only 8 can still be there. 8 goes in slot 1.
   6. 7 has no slot left where it could go. 7 isn't in the code.
   7. Clue 3 has 1 correct digit in a different slot, and 8 is already that one. 1 isn't in slots 3 or 4; 2 isn't in slots 3 or 4; 5 isn't in slot 2.
   8. 1 has no slot left where it could go. 1 isn't in the code.
   9. Clue 6 has no digit in the right slot. 9 isn't in slot 4.
   10. Only 0 can still go in slot 4. 0 goes in slot 4.
   11. Suppose 9 goes in slot 3. Then clue 2 can't be true anymore. 9 isn't in slot 3.
   12. Suppose 3 is in the code. Then clue 6 can't be true anymore. 3 isn't in the code.
   13. Only 5 can still go in slot 3. 5 goes in slot 3.
   14. Clue 1 has 3 digits that aren't in the code, and only 9, 1 and 4 can still be missing. 9 isn't in the code.
   15. Clue 3 has 1 digit in the right slot, and 5 is already that one. 2 isn't in slot 2.
   16. Only 6 can still go in slot 2. 6 goes in slot 2.

5. M5 4 digits, 5 clues

   Guess	Clue
   5231	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   8361	Exactly 2 digits are in the code but in different positions.
   7935	Exactly 2 digits are correct and in the correct positions.
   4596	None of these digits is in the code.
   4386	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to M5Check
   Answer to M5

   The code is 7132. Step by step:

   1. Clue 4 says none of its digits is in the code. 4, 5, 9 and 6 aren't in the code.
   2. Clue 1 has 1 digit that isn't in the code, and 5 is already that one. 2, 3 and 1 are in the code.
   3. Clue 2 has no digit in the right slot. 1 isn't in slot 4; 3 isn't in slot 2; 8 isn't in slot 1.
   4. Clue 2 has 2 digits that aren't in the code, and only 8 and 6 can still be missing. 8 isn't in the code.
   5. Clue 3 needs 2 digits in the right slot, and only 7 and 3 can still be there. 7 goes in slot 1; 3 goes in slot 3.
   6. Clue 1 has 1 digit in the right slot, and 3 is already that one. 2 isn't in slot 2.
   7. The code has 4 digits, and you already know 1, 2, 3 and 7 are in it. 0 isn't in the code.

6. M6 4 digits, 5 clues

   Guess	Clue
   2716	None of these digits is in the code.
   8634	Exactly 3 digits are correct in total, of which 2 are in the correct positions.
   5931	Exactly 2 digits are in the code but in different positions.
   7402	Exactly 1 digit is in the code but in a different position.
   9742	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to M6Check
   Answer to M6

   The code is 8354. Step by step:

   1. Clue 1 says none of its digits is in the code. 2, 7, 1 and 6 aren't in the code.
   2. Clue 2 has 1 digit that isn't in the code, and 6 is already that one. 8, 3 and 4 are in the code.
   3. Clue 3 has no digit in the right slot. 3 isn't in slot 3; 5 isn't in slot 1; 9 isn't in slot 2.
   4. Clue 2 needs 2 digits in the right slot, and only 8 and 4 can still be there. 8 goes in slot 1; 4 goes in slot 4.
   5. Clue 4 has no digit in the right slot. 0 isn't in slot 3.
   6. Clue 4 has 3 digits that aren't in the code, and only 7, 0 and 2 can still be missing. 0 isn't in the code.
   7. Clue 5 has 3 digits that aren't in the code, and only 9, 7 and 2 can still be missing. 9 isn't in the code.
   8. Only 5 can still go in slot 3. 5 goes in slot 3.

4 digits, harder

These need at least one "what if" step: suppose a digit is in the code, follow it through, and see it break a clue.

1. H1 4 digits, 5 clues

   Guess	Clue
   2394	Exactly 2 digits are in the code but in different positions.
   9328	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   9325	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   7896	Exactly 1 digit is correct and in the correct position.
   5178	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to H1Check
   Answer to H1

   The code is 7023. Step by step:

   1. Clue 1 has no digit in the right slot. 2 isn't in slot 1; 3 isn't in slot 2; 4 isn't in slot 4; 9 isn't in slot 3.
   2. Clue 4 has no correct digit in a different slot. 6 isn't in slots 1, 2 or 3; 7 isn't in slots 2, 3 or 4; 8 isn't in slots 1, 3 or 4; 9 isn't in slots 1, 2 or 4.
   3. 9 has no slot left where it could go. 9 isn't in the code.
   4. Clue 2 needs 1 digit in the right slot, and only 2 can still be there. 2 goes in slot 3.
   5. Clue 3 has 1 digit in the right slot, and 2 is already that one. 5 isn't in slot 4.
   6. Clue 5 has no digit in the right slot. 1 isn't in slot 2; 5 isn't in slot 1.
   7. Suppose 1 goes in slot 4. Then clue 4 can't be true anymore. 1 isn't in slot 4.
   8. Suppose 5 goes in slot 2. Then clue 3 can't be true anymore. 5 isn't in slot 2.
   9. 5 has no slot left where it could go. 5 isn't in the code.
   10. Clue 3 has 2 digits that aren't in the code, and 9 and 5 are already those. 3 is in the code.
   11. Clue 1 has 2 digits that aren't in the code, and only 9 and 4 can still be missing. 4 isn't in the code.
   12. Clue 2 has 2 digits that aren't in the code, and only 9 and 8 can still be missing. 8 isn't in the code.
   13. Only 0 can still go in slot 2. 0 goes in slot 2.
   14. Suppose 3 goes in slot 1. Then clue 5 can't be true anymore. 3 isn't in slot 1.
   15. Suppose 6 is in the code. Then slot 4 would have no digit left. 6 isn't in the code.
   16. Clue 4 needs 1 digit in the right slot, and only 7 can still be there. 7 goes in slot 1.

2. H2 4 digits, 7 clues

   Guess	Clue
   8530	Exactly 1 digit is correct and in the correct position.
   2740	Exactly 1 digit is in the code but in a different position.
   5316	Exactly 2 digits are in the code but in different positions.
   1574	Exactly 2 digits are in the code but in different positions.
   7916	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   4708	Exactly 1 digit is in the code but in a different position.
   8523	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to H2Check
   Answer to H2

   The code is 7139. Step by step:

   1. Clue 1 has no correct digit in a different slot. 0 isn't in slots 1, 2 or 3; 3 isn't in slots 1, 2 or 4; 5 isn't in slots 1, 3 or 4; 8 isn't in slots 2, 3 or 4.
   2. Clue 2 has no digit in the right slot. 0 isn't in slot 4; 2 isn't in slot 1; 4 isn't in slot 3; 7 isn't in slot 2.
   3. 0 has no slot left where it could go. 0 isn't in the code.
   4. Clue 3 has no digit in the right slot. 1 isn't in slot 3; 6 isn't in slot 4.
   5. Clue 4 has no digit in the right slot. 1 isn't in slot 1; 4 isn't in slot 4; 5 isn't in slot 2; 7 isn't in slot 3.
   6. 5 has no slot left where it could go. 5 isn't in the code.
   7. Clue 6 has no digit in the right slot. 4 isn't in slot 1.
   8. Clue 7 has no digit in the right slot. 2 isn't in slot 3; 8 isn't in slot 1.
   9. 8 has no slot left where it could go. 8 isn't in the code.
   10. Clue 1 needs 1 digit in the right slot, and only 3 can still be there. 3 goes in slot 3.
   11. Clue 7 has 3 digits that aren't in the code, and only 8, 5 and 2 can still be missing. 2 isn't in the code.
   12. Suppose 9 goes in slot 1. Then clue 5 can't be true anymore. 9 isn't in slot 1.
   13. Suppose 1 goes in slot 4. Then clue 5 can't be true anymore. 1 isn't in slot 4.
   14. Suppose 6 goes in slot 2. Then clue 4 can't be true anymore. 6 isn't in slot 2.
   15. Suppose 9 goes in slot 2. Then clue 4 can't be true anymore. 9 isn't in slot 2.
   16. Clue 5 needs 1 digit in the right slot, and only 7 can still be there. 7 goes in slot 1.
   17. Only 9 can still go in slot 4. 9 goes in slot 4.
   18. 6 has no slot left where it could go. 6 isn't in the code.
   19. Clue 2 has 3 digits that aren't in the code, and only 2, 4 and 0 can still be missing. 4 isn't in the code.
   20. Only 1 can still go in slot 2. 1 goes in slot 2.

3. H3 4 digits, 8 clues

   Guess	Clue
   7609	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   6378	Exactly 2 digits are in the code but in different positions.
   4305	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   2538	Exactly 1 digit is in the code but in a different position.
   9653	Exactly 2 digits are in the code but in different positions.
   3825	Exactly 1 digit is correct and in the correct position.
   2806	Exactly 1 digit is in the code but in a different position.
   0976	Exactly 2 digits are in the code but in different positions.

   Code:

   Your answer to H3Check
   Answer to H3

   The code is 7465. Step by step:

   1. Clue 2 has no digit in the right slot. 3 isn't in slot 2; 6 isn't in slot 1; 7 isn't in slot 3; 8 isn't in slot 4.
   2. Clue 4 has no digit in the right slot. 2 isn't in slot 1; 3 isn't in slot 3; 5 isn't in slot 2.
   3. Clue 5 has no digit in the right slot. 3 isn't in slot 4; 5 isn't in slot 3; 6 isn't in slot 2; 9 isn't in slot 1.
   4. Clue 6 has no correct digit in a different slot. 2 isn't in slots 2 or 4; 5 isn't in slot 1; 8 isn't in slots 1 or 3.
   5. Clue 7 has no digit in the right slot. 0 isn't in slot 3; 6 isn't in slot 4; 8 isn't in slot 2.
   6. 8 has no slot left where it could go. 8 isn't in the code.
   7. Clue 8 has no digit in the right slot. 0 isn't in slot 1; 9 isn't in slot 2.
   8. Suppose 4 goes in slot 4. Then clue 3 can't be true anymore. 4 isn't in slot 4.
   9. Suppose 7 goes in slot 4. Then clue 1 can't be true anymore. 7 isn't in slot 4.
   10. Suppose 3 goes in slot 1. Then clue 3 can't be true anymore. 3 isn't in slot 1.
   11. 3 has no slot left where it could go. 3 isn't in the code.
   12. Clue 2 has 2 digits that aren't in the code, and 3 and 8 are already those. 6 and 7 are in the code.
   13. Clue 1 has 2 digits that aren't in the code, and only 0 and 9 can still be missing. 0 and 9 aren't in the code.
   14. Clue 1 needs 1 digit in the right slot, and only 7 can still be there. 7 goes in slot 1.
   15. Clue 3 needs 1 digit in the right slot, and only 5 can still be there. 5 goes in slot 4.
   16. Clue 3 has 2 digits that aren't in the code, and 3 and 0 are already those. 4 is in the code.
   17. Clue 4 has 3 digits that aren't in the code, and only 2, 3 and 8 can still be missing. 2 isn't in the code.
   18. The code has 4 digits, and you already know 4, 5, 6 and 7 are in it. 1 isn't in the code.
   19. Only 4 can still go in slot 2. 4 goes in slot 2.

4. H4 4 digits, 6 clues

   Guess	Clue
   0657	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   0695	Exactly 2 digits are in the code but in different positions.
   7430	Exactly 3 digits are in the code but in different positions.
   9486	Exactly 1 digit is in the code but in a different position.
   1560	Exactly 2 digits are correct in total, of which 1 is in the correct position.
   2973	Exactly 1 digit is in the code but in a different position.

   Code:

   Your answer to H4Check
   Answer to H4

   The code is 4507. Step by step:

   1. Clue 2 has no digit in the right slot. 0 isn't in slot 1; 5 isn't in slot 4; 6 isn't in slot 2; 9 isn't in slot 3.
   2. Clue 3 has no digit in the right slot. 0 isn't in slot 4; 3 isn't in slot 3; 4 isn't in slot 2; 7 isn't in slot 1.
   3. Clue 4 has no digit in the right slot. 6 isn't in slot 4; 8 isn't in slot 3; 9 isn't in slot 1.
   4. Clue 6 has no digit in the right slot. 2 isn't in slot 1; 3 isn't in slot 4; 7 isn't in slot 3; 9 isn't in slot 2.
   5. Suppose 2 is in the code. Then clue 3 can't be true anymore. 2 isn't in the code.
   6. Suppose 4 isn't in the code. Then clue 6 can't be true anymore. 4 is in the code.
   7. Clue 4 has 3 digits that aren't in the code, and only 9, 8 and 6 can still be missing. 9, 8 and 6 aren't in the code.
   8. Clue 1 has 1 digit that isn't in the code, and 6 is already that one. 0, 5 and 7 are in the code.
   9. Clue 3 has 1 digit that isn't in the code, and only 3 can still be missing. 3 isn't in the code.
   10. Clue 5 has 2 digits that aren't in the code, and only 1 and 6 can still be missing. 1 isn't in the code.
   11. Clue 5 needs 1 digit in the right slot, and only 5 can still be there. 5 goes in slot 2.
   12. Only 4 can still go in slot 1. 4 goes in slot 1.

5 digits

The longest codes, with up to nine clues. Keep a grid of digits and positions on scrap paper.

1. E1 5 digits, 9 clues

   Guess	Clue
   74890	Exactly 2 digits are in the code but in different positions.
   16523	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   47396	Exactly 1 digit is correct and in the correct position.
   89024	Exactly 2 digits are in the code but in different positions.
   28306	Exactly 2 digits are in the code but in different positions.
   76451	Exactly 3 digits are in the code but in different positions.
   73408	Exactly 2 digits are in the code but in different positions.
   13847	Exactly 2 digits are in the code but in different positions.
   13095	Exactly 3 digits are in the code but in different positions.

   Code:

   Your answer to E1Check
   Answer to E1

   The code is 07512. Step by step:

   1. Clue 1 has no digit in the right slot. 0 isn't in slot 5; 4 isn't in slot 2; 7 isn't in slot 1; 8 isn't in slot 3; 9 isn't in slot 4.
   2. Clue 3 has no correct digit in a different slot. 3 isn't in slots 1, 2, 4 or 5; 4 isn't in slots 3, 4 or 5; 6 isn't in slots 1, 2, 3 or 4; 7 isn't in slots 3, 4 or 5; 9 isn't in slots 1, 2, 3 or 5.
   3. 9 has no slot left where it could go. 9 isn't in the code.
   4. Clue 4 has no digit in the right slot. 0 isn't in slot 3; 2 isn't in slot 4; 8 isn't in slot 1.
   5. Clue 5 has no digit in the right slot. 0 isn't in slot 4; 2 isn't in slot 1; 3 isn't in slot 3; 6 isn't in slot 5; 8 isn't in slot 2.
   6. 3 has no slot left where it could go. 3 isn't in the code.
   7. 6 has no slot left where it could go. 6 isn't in the code.
   8. Clue 2 has 2 digits that aren't in the code, and 6 and 3 are already those. 1, 5 and 2 are in the code.
   9. Clue 6 has no digit in the right slot. 1 isn't in slot 5; 5 isn't in slot 4.
   10. Clue 7 has no digit in the right slot. 8 isn't in slot 5.
   11. Clue 8 has no digit in the right slot. 1 isn't in slot 1.
   12. Clue 2 needs 1 digit in the right slot, and only 5 can still be there. 5 goes in slot 3.
   13. Only 2 can still go in slot 5. 2 goes in slot 5.
   14. Clue 9 has 2 digits that aren't in the code, and 3 and 9 are already those. 0 is in the code.
   15. Clue 4 has 3 digits that aren't in the code, and only 8, 9 and 4 can still be missing. 8 and 4 aren't in the code.
   16. Only 0 can still go in slot 1. 0 goes in slot 1.
   17. Only 1 can still go in slot 4. 1 goes in slot 4.
   18. Only 7 can still go in slot 2. 7 goes in slot 2.

2. E2 5 digits, 8 clues

   Guess	Clue
   06871	Exactly 2 digits are in the code but in different positions.
   25198	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   37085	Exactly 2 digits are in the code but in different positions.
   26398	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   84513	Exactly 1 digit is in the code but in a different position.
   27031	Exactly 2 digits are in the code but in different positions.
   83701	Exactly 1 digit is correct and in the correct position.
   34582	Exactly 2 digits are in the code but in different positions.

   Code:

   Your answer to E2Check
   Answer to E2

   The code is 52796. Step by step:

   1. Clue 1 has no digit in the right slot. 0 isn't in slot 1; 1 isn't in slot 5; 6 isn't in slot 2; 7 isn't in slot 4; 8 isn't in slot 3.
   2. Clue 3 has no digit in the right slot. 0 isn't in slot 3; 3 isn't in slot 1; 5 isn't in slot 5; 7 isn't in slot 2; 8 isn't in slot 4.
   3. Clue 5 has no digit in the right slot. 1 isn't in slot 4; 3 isn't in slot 5; 4 isn't in slot 2; 5 isn't in slot 3; 8 isn't in slot 1.
   4. Clue 6 has no digit in the right slot. 2 isn't in slot 1; 3 isn't in slot 4.
   5. Clue 7 has no correct digit in a different slot. 0 isn't in slots 2 or 5; 1 isn't in slots 1, 2 or 3; 3 isn't in slot 3; 7 isn't in slots 1 or 5; 8 isn't in slots 2 or 5.
   6. 1 has no slot left where it could go. 1 isn't in the code.
   7. 8 has no slot left where it could go. 8 isn't in the code.
   8. Clue 2 has 2 digits that aren't in the code, and 1 and 8 are already those. 2, 5 and 9 are in the code.
   9. Clue 4 needs 1 digit in the right slot, and only 9 can still be there. 9 goes in slot 4.
   10. 0 has no slot left where it could go. 0 isn't in the code.
   11. Clue 1 has 3 digits that aren't in the code, and 0, 8 and 1 are already those. 6 and 7 are in the code.
   12. Clue 2 has 1 digit in the right slot, and 9 is already that one. 5 isn't in slot 2.
   13. Clue 3 has 3 digits that aren't in the code, and only 3, 0 and 8 can still be missing. 3 isn't in the code.
   14. Only 2 can still go in slot 2. 2 goes in slot 2.
   15. Clue 5 has 4 digits that aren't in the code, and only 8, 4, 1 and 3 can still be missing. 4 isn't in the code.
   16. Only 6 can still go in slot 5. 6 goes in slot 5.

3. E3 5 digits, 9 clues

   Guess	Clue
   98214	Exactly 2 digits are in the code but in different positions.
   81537	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   30198	Exactly 2 digits are in the code but in different positions.
   03916	Exactly 2 digits are in the code but in different positions.
   61285	Exactly 2 digits are in the code but in different positions.
   05197	Exactly 4 digits are in the code but in different positions.
   17429	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   98351	Exactly 2 digits are in the code but in different positions.
   96108	Exactly 2 digits are in the code but in different positions.

   Code:

   Your answer to E3Check
   Answer to E3

   The code is 14570. Step by step:

   1. Clue 1 has no digit in the right slot. 1 isn't in slot 4; 2 isn't in slot 3; 4 isn't in slot 5; 8 isn't in slot 2; 9 isn't in slot 1.
   2. Clue 3 has no digit in the right slot. 0 isn't in slot 2; 1 isn't in slot 3; 3 isn't in slot 1; 8 isn't in slot 5; 9 isn't in slot 4.
   3. Clue 4 has no digit in the right slot. 0 isn't in slot 1; 3 isn't in slot 2; 6 isn't in slot 5; 9 isn't in slot 3.
   4. Clue 5 has no digit in the right slot. 1 isn't in slot 2; 5 isn't in slot 5; 6 isn't in slot 1; 8 isn't in slot 4.
   5. Clue 6 has no digit in the right slot. 5 isn't in slot 2; 7 isn't in slot 5.
   6. Clue 8 has no digit in the right slot. 1 isn't in slot 5; 3 isn't in slot 3; 5 isn't in slot 4.
   7. Clue 9 has no digit in the right slot. 0 isn't in slot 4; 6 isn't in slot 2.
   8. Suppose 0 isn't in the code. Then clue 8 can't be true anymore. 0 is in the code.
   9. Suppose 3 is in the code. Then clue 6 can't be true anymore. 3 isn't in the code.
   10. Suppose 5 goes in slot 1. Then clue 2 can't be true anymore. 5 isn't in slot 1.
   11. Suppose 8 goes in slot 1. Then clue 2 can't be true anymore. 8 isn't in slot 1.
   12. Clue 2 needs 1 digit in the right slot, and only 5 can still be there. 5 goes in slot 3.
   13. 8 has no slot left where it could go. 8 isn't in the code.
   14. Clue 2 has 2 digits that aren't in the code, and 8 and 3 are already those. 1 and 7 are in the code.
   15. Clue 3 has 3 digits that aren't in the code, and only 3, 9 and 8 can still be missing. 9 isn't in the code.
   16. Clue 4 has 3 digits that aren't in the code, and only 3, 9 and 6 can still be missing. 6 isn't in the code.
   17. Clue 5 has 3 digits that aren't in the code, and only 6, 2 and 8 can still be missing. 2 isn't in the code.
   18. Clue 1 has 3 digits that aren't in the code, and 9, 8 and 2 are already those. 4 is in the code.
   19. Clue 7 has 1 digit in the right slot, and 1 is already that one. 7 isn't in slot 2.
   20. Only 4 can still go in slot 2. 4 goes in slot 2.
   21. Only 7 can still go in slot 4. 7 goes in slot 4.

4. E4 5 digits, 7 clues

   Guess	Clue
   93106	Exactly 2 digits are in the code but in different positions.
   68190	Exactly 3 digits are in the code but in different positions.
   09364	Exactly 2 digits are in the code but in different positions.
   68743	Exactly 3 digits are correct in total, of which 1 is in the correct position.
   60493	Exactly 2 digits are in the code but in different positions.
   63701	Exactly 2 digits are in the code but in different positions.
   03854	Exactly 3 digits are correct in total, of which 1 is in the correct position.

   Code:

   Your answer to E4Check
   Answer to E4

   The code is 16845. Step by step:

   1. Clue 1 has no digit in the right slot. 0 isn't in slot 4; 1 isn't in slot 3; 3 isn't in slot 2; 6 isn't in slot 5; 9 isn't in slot 1.
   2. Clue 2 has no digit in the right slot. 0 isn't in slot 5; 6 isn't in slot 1; 8 isn't in slot 2; 9 isn't in slot 4.
   3. Clue 3 has no digit in the right slot. 0 isn't in slot 1; 3 isn't in slot 3; 4 isn't in slot 5; 6 isn't in slot 4; 9 isn't in slot 2.
   4. Clue 5 has no digit in the right slot. 0 isn't in slot 2; 3 isn't in slot 5; 4 isn't in slot 3.
   5. Clue 6 has no digit in the right slot. 1 isn't in slot 5; 7 isn't in slot 3.
   6. Clue 4 needs 1 digit in the right slot, and only 4 can still be there. 4 goes in slot 4.
   7. Clue 7 needs 1 digit in the right slot, and only 8 can still be there. 8 goes in slot 3.
   8. 0 has no slot left where it could go. 0 isn't in the code.
   9. Suppose 1 isn't in the code. Then clue 3 can't be true anymore. 1 is in the code.
   10. Suppose 3 is in the code. Then clue 2 can't be true anymore. 3 isn't in the code.
   11. Clue 7 has 2 digits that aren't in the code, and 0 and 3 are already those. 5 is in the code.
   12. Suppose 2 is in the code. Then clue 1 can't be true anymore. 2 isn't in the code.
   13. Suppose 6 isn't in the code. Then the code would need too many digits. 6 is in the code.
   14. Clue 1 has 3 digits that aren't in the code, and only 9, 3 and 0 can still be missing. 9 isn't in the code.
   15. Clue 4 has 2 digits that aren't in the code, and only 7 and 3 can still be missing. 7 isn't in the code.
   16. Only 5 can still go in slot 5. 5 goes in slot 5.
   17. Only 1 can still go in slot 1. 1 goes in slot 1.

A quick method

1. Cross out the none clues.

   Every digit in a "none of these" clue is gone, everywhere.

2. Use those cross outs on the other clues.

   Once a clue's dead digits are gone, its count often has only one way to fit.

3. Place digits by position.

   A digit that's "in the code but in a different position" can't sit where that guess had it.

4. Try a what if.

   When you're stuck, suppose a digit is in the code and follow the clues. If one breaks, the digit is out.

The full guide to solving code breaker puzzles works through three puzzles step by step, including the famous 682 riddle.

How these were made

The puzzles come from the generator in my game Crack the Vault, the same one behind the daily code breaker on this site. Each answer above was written by the same step by step solver that gives the hints in the daily code breaker, so every step is one you can follow with a pencil. Before the page goes up, a separate program tries every possible code against every clue to make sure exactly one fits.

Questions

Crack the Vault
500 levels from 3 to 5 digits, a daily vault, and hints that explain the next step.

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