Rainbow Sudoku

(MathPickle 2021 – Inspired by Amar Sodhi)

In regular sudoku and pentomino sudoku numbers are given as clues. Each region needs exactly one copy of each number. That’s true whether the regions are 3×3 squares or pentominoes.

In Rainbow Sudoku, some numbers and some regions are given as clues. It’s your job to find all the numbers and all the regions. Sometimes only fragments of a region are identified. It’s your job to find all the remaining bits of that region.

It will be useful to have five or six coloured pencils.

Here is a pdf of some puzzles. These pages are for projecting to the whole class. They come with answers.

Here is a pdf of the puzzles for passing around to pairs of students. There are no answers.

Rainbow Sudoku

new & improved!
(MathPickle 2021 – Inspired by Amar Sodhi)

These puzzles are a better design and a bit harder than the ones on the left. You will never be given an entire shape as a hint… only parts of it.

On the puzzles on the left the color of a region is often interchangeable with another region. With these new Rainbow Sudoku, each region will have just one color.

It will be useful to have six coloured pencils.

Here is a pdf of the puzzles for passing around to pairs of students. There are no answers.

Standards for Mathematical Practice

MathPickle puzzle and game designs engage a wide spectrum of student abilities while targeting the following Standards for Mathematical Practice:

MP1 Toughen up!

Students develop grit and resiliency in the face of nasty, thorny problems. It is the most sought after skill for our students.

MP2 Think abstractly!

Students take problems and reformat them mathematically. This is helpful because mathematics lets them use powerful operations like addition.

MP3 Work together!

Students discuss their strategies to collaboratively solve a problem and identify missteps in a failed solution. MathPickle recommends pairing up students for all its puzzles.

MP4 Model reality!

Students create a model that mimics the real world. Discoveries made by manipulating the model often hint at something in the real world.

MP5 Use the right tools!

Students should use the right tools: 0-99 wall charts, graph paper, mathigon.org. etc.

MP6 Be precise!

Students learn to communicate using precise terminology. MathPickle encourages students not only to use the precise terms of others, but to invent and rigorously define their own terms.

MP7 Be observant!

Students learn to identify patterns. This is one of the things that the human brain does very well. We sometimes even identify patterns that don't really exist 😉

MP8 Be lazy!?!

Students learn to seek for shortcuts. Why would you want to add the numbers one through a hundred if you can find an easier way to do it?


Please use MathPickle in your classrooms. If you have improvements to make, please contact me. I'll give you credit and kudos 😉 For a free poster of MathPickle's ideas on elementary math education go here.

Gordon Hamilton

(MMath, PhD)