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Factor Tree Puzzles Inspired by Dr. Harold Reiter

Yesterday, I shared about all the amazing things I learned/experienced as part of the Tulsa Math Teachers’ Circle Summer Immersion Workshop. As part of that post, I mentioned that I had created some factor tree puzzles after being inspired by the puzzles shared by Dr. Harold Reiter and the puzzle created by one of the other participants.

factor tree puzzles

These puzzles involve a factor tree in which each terminating leg of the tree represents a prime number. Each variable represents a unique digit. So, if a is equal to five, then b cannot be equal to five.

I really enjoyed solving the puzzle created by another teacher in our group, so I decided I should try my hand at creating my own puzzles. 

Factor Tree Puzzle Inspired by Dr. Harold Reiter

Here are the four puzzles I ended up creating myself. In all honesty, I created way more than four puzzles. But, many of the puzzles I created turned out to have multiple solutions or mistakes. These four puzzles have been verified by both my husband and myself to have only one solution.

I decided to place circles around the prime numbers to further clarify the puzzles. 

Factor Tree Puzzle Inspired by Dr. Harold Reiter
Factor Tree Puzzle Inspired by Dr. Harold Reiter
Factor Tree Puzzle Inspired by Dr. Harold Reiter
Factor Tree Puzzle Inspired by Dr. Harold Reiter

The difficulty level definitely increases as the puzzle number increases. Puzzle 1 is the easiest. Puzzles 2 and 3 are trickier. And, Puzzle 4 is a beast. It took two people with math degrees a very long time to verify that there was one solution. So, I would NOT recommend giving puzzle 4 to students. Unless of course, there’s some logical step that makes solving it much easier than the route my husband and I ended up taking!

Free Download of Factor Tree Puzzles

Factor Tree Puzzles (PPT) (1639 downloads )

Factor Tree Puzzles (PDF) (1682 downloads )

I hope you enjoy trying your hand at this new-to-me type of puzzle!

P.S. I’m excited to say that my first factor tree puzzle was featured in Jo Morgan‘s 91st Maths Gems post. If you’re not following her Resourceaholic blog, you are missing out!

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.


Tuesday 14th of January 2020



Wednesday 23rd of October 2019

Do you have the answer sheet posted anywhere?


Sunday 15th of September 2019

Are the answers posted anywhere?

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