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U Sums Puzzle

The U Sums Puzzle is a number-placing puzzle involving the digits from 1 to 7. Can you make each line sum to 12?

U Sums Number Puzzle.

Puzzle Instructions

Places the numbers 1 to 7 in the spaces on the U-shaped gameboard so that the sum of the numbers in each of the three lines is equal to 12.

This puzzle is a twist on a magic square puzzle where each row, column, or diagonal in a square have to have the same sum.

Puzzle Source

I ran across this puzzle in a collection of 199 different mathematical puzzles that is offered as a free download from IREM de Lyon. This is a top-notch puzzle resource if you speak French.

The U Sums Puzzle is the 26th puzzle (Trois sommes en U) shared in the downloadable PDF file.

I sadly do not speak French, but I was able to use the Google Translate app to translate quite a few of the puzzle instructions in order to use them in my classroom. Last week, I shared the Magic H Puzzle which is from this same resource.

March 2024 Update: I have also translated the Equal Sums Puzzle and the Lines of 3 Puzzle from the same resource!

Printing and Prepping the Puzzle

Print the puzzle instructions/puzzle board on plain copy paper. The second page of the file contains the number tiles for the numbers from 1-7. I suggest printing these number tiles on colored paper such as Astrobrights.

U Sums Puzzle Screenshot.
Page 1
u sums puzzle puzzle pieces.
Page 2

To make the puzzle pieces more durable, I suggest running the pages through a laminator before using the puzzles with students.


drawing of laminator machine with text "laminating recommendations"

A laminator is a MUST-HAVE for me as a math teacher! I spent my first six years as a teacher at a school with a broken laminator, so I had to find a way to laminate things myself.

I’ve had several laminators over the years. I currently use a Scotch laminator at home and a Swingline laminator at school.

I highly recommend splurging a bit on the actual laminator and buying the cheapest laminating pouches you can find!

I laminate all of my puzzles, and I am then able to use the same puzzles over and over again for years and years. I currently have some puzzles that I am using for the 7th year in a row!

Tips for Using this Puzzle in the Classroom

I used the U Sums Puzzle with my students several weeks ago as one of our Puzzles of the Week.

u sums puzzle hanging under sign reading "puzzle of the week"

I hang my weekly puzzles on the dry erase board in these fabulous magnetic pockets that I ordered from Charles Leonard on Amazon.

When students get to class, they often grab one of the puzzles off the dry erase board and take it to their desk to work on before class starts. Other students gravitate towards the puzzles when they finish early.

This U Sums is definitely on the EASIER side of the puzzles I tend to share here on my blog. This makes it suitable for using as a brain break or a class opener activity since students should need only a few minutes to solve it.

Puzzle Solutions

I intentionally do not make answers to the printable math puzzles I share on my blog available online because I strive to provide learning experiences for my students that are non-google-able. I would like other teachers to be able to use these puzzles in their classrooms as well without the solutions being easily found on the Internet.

However, I do recognize that us teachers are busy people and sometimes need to quickly reference an answer key to see if a student has solved a puzzle correctly or to see if they have interpreted the instructions properly.

If you are a teacher who is using these puzzles in your classroom, please send me an email at with information about what you teach and where you teach. I will be happy to forward an answer key to you.

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