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Kode #103: hints & solution

Here's the clue board for Kode #103. Start with the spoiler-free hints. If you're still stuck, the full step-by-step solution is below, hidden until you open it.

The clue board

Each row is a guess that's already been graded. ▲ means a right digit in the right spot; ● means a right digit in the wrong spot.

  • 16502▲1●1
  • 26072▲0●2
  • 37946▲0●2
  • 49763▲0●2
  • 53624▲0●0

Spoiler-free hints

  • Exactly one of the four digits is even.
  • The four digits add up to 21.
  • 3 of the digits are 5 or higher.

Try the hints first. The solution below walks through every deduction.

Step-by-step solution

Every Kode can be cracked by pure deduction, with no guessing. This board falls in 9 logical steps. Open the solution to follow them one at a time.

Show the solution · reveals the code

When a row "rules out" a position, it shows that digit there but its ▲ marks are already used up (or it has none), so the digit can't sit there.

  1. Row 5 (3 6 2 4) has no marks at all, so 3, 6, 2, and 4 are not in the code.
  2. Row 1 (6 5 0 2) has 2 marks still unexplained, and only 2 digits are left undecided: 5 and 0. So both are in the code.
  3. Row 2 (6 0 7 2) has one mark still unexplained, and only one digit is left undecided: 7. So it is in the code.
  4. Row 3 (7 9 4 6) has one mark still unexplained, and only one digit is left undecided: 9. So it is in the code.
  5. That makes all four digits of the code: 0, 5, 7, and 9. Every other digit is out, which also rules out 1 and 8.
  6. The 7 has only one spot left: position 4 (row 3 rules out position 1, row 4 rules out position 2, and row 2 rules out position 3).
  7. The 9 has only one spot left: position 3 (row 4 rules out position 1, row 3 rules out position 2, and position 4 is already 7).
  8. Row 1 (6 5 0 2) has one digit in the right spot. Since position 3 is already 9, it has to be the 5 in position 2.
  9. That leaves the 0 for position 1.

That cracks it: the code is 0597.

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