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Logic Puzzle Friday: Locked Treasure Code

Very large Treasure Chest set in front of a weeping willow tree.

Logic Puzzle Friday: Locked Treasure Code

Logic Puzzle Friday: Brain Workout Series

Welcome to Week 5 — the grand finale of our 5-week Logic Grids & Deductions brain workout series! We are wrapping up our first month with a treasure hunt that focuses on pattern recognition and subset elimination. Number lock puzzles are highly engaging because they turn abstract mathematical thinking into a hands-on game. To break the code, students cannot rely on guesswork; they must cross-reference multiple constraints to eliminate impossible digits one by one. This builds a strong foundational understanding of variables, sets, and systematic data analysis — the very skills needed for algebraic equations and science labs. Can you crack the code to The Locked Treasure?

The Week 5 Puzzle: The Locked Treasure

Close-up of a rusty padlock secured to a chain post, symbolizing security. Blocks added for the three digits.
Reference image by Lyncoln Miller via Pexels
You find an ancient treasure chest locked with a three-digit combination code (_  _  _). Next to the lock, you find a parchment containing five sample guesses along with clues about how accurate each guess is.    

The Challenge:

Using these five clues, what is the exact three-digit code to unlock the treasure chest? A parchment containing five sample guesses along with clues about how accurate each guess is:

GUESS   |  CLUE / ACCURACY
+-------+
 6  8  2  |   One digit is correct and WELL-PLACED.
 6  1  4   |   One digit is correct but WRONG-PLACED.
 2  0  6  |  Two digits are correct but BOTH WRONG-PLACED.
 7  3  8  |  ALL digits are COMPLETELY WRONG.
3  8  0   |  One digit is correct but WRONG-PLACED.
   

Start with Clue #4 (7 3 8)! Since all of those digits are completely wrong, cross out every 7, 3, and 8 on the entire parchment. That instantly narrows down your options!

🏆 The Unlocking Code: 0 4 2


Step-by-Step Logic Breakdown:

  1. Eliminate the “Zero-Value” Digits

Look at Clue #4 (7 3 8). The clue states that all digits are completely wrong. This means the combination does not contain a 7, 3, or 8. Cross out every 7, 3, and 8 across all clues.

  1. Find the Digit ‘2’ and Its Exact Position

Look at Clue #1 (6 8 2). Since 8 is eliminated, the one correct digit must be either 6 or 2.

Now compare this with Clue #3 (2 0 6):

  • If 6 were the correct digit, Clue #1 says it is “well-placed” (at the front), but Clue #3 says it is “wrong-placed” (at the end). A digit cannot be in the front and back at the same time, so 6 must be WRONG.
  • This proves 2 is the correct digit. Clue #1 tells us 2 is “well-placed” (at the end).

Current Code: __ __ 2

  1. Find the Digit ‘0’ and Its Position

Revisiting Clue #3 (2 0 6), we know 6 is wrong and 2 is right. This means 0 must be the second correct digit.

  • Clue #3 tells us 0 is “wrong-placed” (meaning it cannot be in the middle spot).
  • Clue #5 (3 8 0) also states 0 is “wrong-placed” (meaning it cannot be in the end spot).
  • Since 0 cannot be in the middle or at the end, 0 must go at the front!

Current Code:  0 __ 2

  1. Identify the Final Digit

Look at Clue #2 (6 1 4):

  • We already proved 6 is wrong.
  • 1 cannot be correct because Clue #5 (3 8 0) established that 0 was the only correct digit in that set.
  • This leaves 4 as the final correct digit. Clue #2 notes that 4 is “wrong-placed” (at the end), so it fits perfectly into the remaining middle spot.

The lock clicks open: 0 4 2!


 

Turn Problem-Solving Games into Classroom Mastery

Very large Treasure Chest set in front of a weeping willow tree.
Image by Kira Kira Rottstock from Pixabay

Puzzles like “The Locked Treasure” teach students that complex math problems aren’t overwhelming when you break them down using systematic elimination. When students build strong logical habits, word problems and algebra equations become second nature!

Whether your child is working through foundational elementary arithmetic, strengthening high school algebra skills, or preparing for college entrance exams, MyTutorLesson offers personalized, expert tutoring tailored to how your student learns best.


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