Kode #100: hints & solution
Here's the clue board for Kode #100. 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.
- 17638▲1●1
- 27930▲0●1
- 34798▲0●1
- 42914▲0●2
- 57981▲0●0
Spoiler-free hints
- 3 of the four digits are even.
- The four digits add up to 15.
- Just one digit is 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 10 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.
- Row 5 (7 9 8 1) has no marks at all, so 7, 9, 8, and 1 are not in the code.
- Row 1 (7 6 3 8) has 2 marks still unexplained, and only 2 digits are left undecided: 6 and 3. So both are in the code.
- Row 2 (7 9 3 0) has one mark, already accounted for by 3. That rules out 0.
- Row 3 (4 7 9 8) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
- Row 4 (2 9 1 4) has one mark still unexplained, and only one digit is left undecided: 2. So it is in the code.
- That makes all four digits of the code: 2, 3, 4, and 6. Every other digit is out, which also rules out 5.
- Row 1 (7 6 3 8) has one digit in the right spot. Since row 2 rules out the 3 in position 3, it has to be the 6 in position 2.
- The 4 has only one spot left: position 3 (row 3 rules out position 1, row 4 rules out position 4, and position 2 is already 6).
- The 2 has only one spot left: position 4 (row 4 rules out position 1, position 2 is already 6, and position 3 is already 4).
- That leaves the 3 for position 1.
That cracks it: the code is 3642.