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X Marks the Spot Puzzle

I ran across this X Marks the Spot Puzzle several years ago. The goal of the puzzle is to place Xs in the drawing so that a certain set of requirements is met.

After typing up this puzzle with several other brainteasers, I promptly misplaced the computer file before ever using any of the puzzles with my students. Several months ago, I ran across the file and decided I needed to use the puzzles in my classroom and share them here on the blog.

Sadly, past me was not always the best at recording the source of the puzzles I found. I have searched and searched and searched, and I cannot find this puzzle online anywhere. If you know of the original source, please let me know so I can give credit where credit is due!

X Marks the Spot Puzzle

In X Marks the Spot, you are tasked with placing Xs in a drawing to meet certain requirements. Place Xs in the drawing so that:

  • exactly two Xs are within the triangle and circle only,
  • exactly two Xs are within the square and circle only,
  • exactly five Xs are in the triangle, and
  • there are a total of ten Xs within the circle.

I plan on using this puzzle with my students in a dry erase pocket to make it easy for them to draw/erase Xs.

If you don’t have a classroom set of dry erase pockets, you could also use heavy duty sheet protectors. But, I highly recommend investing in a classroom set of the pockets since they are so much more durable.

X Marks the Spot Puzzle

Digital Version of X Marks the Spot Puzzle

Kathy Henderson has created a Desmos Activity Builder version of the X Marks the Spot Puzzle.

More Dry Erase Puzzles

Laura Miller

Tuesday 15th of November 2022

Hi Sarah! I love, love, love your site!! I use a lot of the puzzles with my fifth grade advanced math class, and they're able to solve a lot of them. By any chance do you have a master answer key for most of the puzzles? Sometimes, on the spot, they'll ask me specific questions, and while I've spent hours figuring out the solutions, having a key would be much easier. If you could email it to me, I'd greatly appreciate it. Laura

Shelbey Wheat

Wednesday 2nd of November 2022

Do you have an answer to this puzzle X marks the spot? I am a gifted and talented teacher in a suburb of Dallas, TX. I have given this puzzle to my 5th graders and we have been having quite the discussion.

Thank you! Ms. Wheat


Monday 28th of March 2022

Can you send me the solution for this puzzle?