# Domino Pyramid Puzzle

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I typed up this Domino Pyramid Puzzle from L.P. Mochalov to use with these sets of dominoes that I purchased last summer from Dollar Tree.

Dollar Tree’s dominoes (shown below on the right) are slightly smaller than a standard-sized domino, but you definitely can’t beat the price!

I was reminded the other day when posting about Leonid Mochalov’s Chess Cube Puzzle that I had added several of the domino puzzles from Totally Tough Brainteasers on my list of puzzles to recreate for my classroom. This puzzle is also featured for free on Mochalov’s Puzzle Website.

The first puzzle that caught my eye was Mochalov’s Domino Pyramid Puzzle. The goal of this puzzle is to arrange a full set of dominoes into the provided pyramid template so that the sum of every row is a perfect square. Additionally, the domino sides which touch must have the same number in each horizontal row.

Mochalov words this slightly differently in his instructions. He writes “the tiles in the horizontal rows are positioned according to the rules of dominoes.” I grew up playing dominoes throughout my childhood, so I understood exactly what the instructions meant. But, I wasn’t sure if my students would have the same familiarity with the rules of dominoes.

I added a list of the perfect squares under 100 to the bottom of the puzzle template for students (or adults!) to use as a reference.

You have several different options for dominoes that can be placed in the first row. I chose the 2:2 domino since 2+2=4 which is a perfect square.

To demonstrate the second rule (domino sides which touch in each horizontal row must have the same number), I chose the 4:2 and 2:1 dominoes for the second row since 4+2+2+1=9.

After photographing this, I realized that this wasn’t the best example because I ended up matching numbers both horizontally and vertically. Only the dominoes in each horizontal row have to match when touching.

For example, I could switch out the top row for a 6:3 domino since 6+3=9 which is a perfect square.

Now, the tricky part of the puzzle is figuring out how to fill out the entire pyramid grid with a single set of dominoes!

So next time you are at Dollar Tree, pick up a set or two or three or ten of dominoes. I’ve got an entire list of other domino puzzles that I plan on typing up to use with my students. And, you know that I will be sharing the files with you as well!

If you have standard sized dominoes in your classroom, I also created a larger version of this Domino Pyramid Puzzle that prints on 11 x 17 cardstock.

## 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 sarah@mathequalslove.net with information about what you teach and where you teach. I will be happy to forward an answer key to you.