Yohaku Puzzle

In the tradition of “the answer is always a spreadsheet” I converted a Yohaku puzzle I saw on Twitter into a Google Sheets spreadsheet. Bonus for being a spreadsheet it generates unlimited puzzles, so students are not all doing the same thing. Conditional formatting automatically checks the student’s work so they get immediate feedback.



Yohaku Puzzle – Addition

Fill in cells with 9 consecutive odd numbers to get totals in each row/column.

Yohaku Puzzle

I’m a math teacher so “9 consecutive odd numbers” made me excited. Finally an excuse to use the 2n+1 from Algebra!!! I might have had too much fun coding this puzzle.

4 C’s Check

Most worksheets have NONE of the 4C’s. Let’s see how many this one has.

DOK 3 Strategic Thinking (Critical Thinking)

Math puzzles like this can be great for having strategic thinking math conversations. It’s also a great hook into a lesson on consecutive integers 🙂 You don’t have to be an Algebra student to enjoy these puzzles! You can find more on the Yohaku website.

Creative Thinking

Not collecting 30 of the same thing. Students will come up with creative (and different) strategies to solve the puzzles.


Students are going to have to talk these problems out. Suggest students work in pairs or groups to strategize a solution together. But regardless, it’s Google Sheets so it has collaboration baked in. Students can share puzzles and insert feedback comments to help each other think out the reasoning.

Clearly Communicate Ideas

If we ask students to share their strategy

Yohaku Menu

Get started by using the Yohaku menu. (Note, I coded this with Google Apps Script so it must be generated from a computer; not mobile. However, once the puzzle is generated it can be shared and used on mobile.) Choose “Create Puzzle” from the menu.
Yohaku Puzzle menu

Email Address

You will then be prompted to enter an email address. The answer key is emailed to that address, the spreadsheet is shared with that email address and the person is linked back to the spreadsheet. In other words, the kids should enter the teacher’s email address 🙂 If an invalid (or none) email is entered a pop-up window will list the answer key.
Email Address

Unlimited Puzzles

You can use the menu multiple times, an additional sheet will be created with an additional puzzle.


Enter numerical values into the yellow cells such that the rows and columns add up to the summed number on the edges. If the column or row adds up to the summed value on the edge, it will format green.
Consecutive odd integers puzzle

Notice in my example I was able to get the 3rd column to sum to 43, however number sense… can 5 be part of the set of numbers if 13, 15, 17 and 21 are in the data set? Remember to get students to talk about their strategy and defend their reasoning!

35 plus 35 plus 35

My 11 year old was trying out this puzzle. At first, he typed in 103 in the column that is supposed to add up to 105. So we talked about… what is the range of possible values if you use the number 103? 103, 105, 107, 109, 111, 113, 115, 117, 119 IF 103 was the smallest number. 103, 101, 99, 97, 95, 93, 91, 89, 87 IF 103 was the largest number. Or it is somewhere in between the 9 consecutive odd integers. Could the sum of 3 of these numbers between 87 and 119 add up to 105? No. Any 3 of these numbers would exceed 105.

So he deleted that. He then observed that 35 + 35 + 35 = 105. Great, except then you don’t have consecutive odd integers. And the “consecutive” are within the grid of 9, not necessarily the 3 cells in a row!! My son asked me “Could there be a 33 and a 37 but not a 35?” Well…. you tell me, can there? No, if you have consecutive you need all the ones in between.

So you can see how he and I were having some great number sense conversations as he worked out this puzzle.

Don’t Delete Mistakes

Another advantage to using a spreadsheet is you do not have to lose the mistakes. As Stanford math professor Jo Boaler says, mistakes are part of the learning process. We want to see the student’s strategic thinking. Hard to do that if they delete their attempts. Can’t talk about the students series of strategies if they don’t have a series of strategies.

Duplicate the Tab

When the student makes a mistake, have them DUPLICATE the sheet by clicking on the tiny triangle on the tab and choosing “Duplicate.” Then they can apply a new strategy. Hopefully, the student ends up with a lot a lot of tabs along the bottom as they work through their thinking.
Duplicate the tab

SlideShot to Communicate Ideas

This activity might be a good excuse to try out SlideShot Chrome extension.

Students click on the Chrome extension to start automatically taking a screenshot every minute. This will capture the strategy and process along the way. Students can add a manual capture as they see fit. The slides are automatically saved to a folder in Google Drive. Upon clicking Finish, the screenshots are automatically added to a Google Slides presentation. Each slide has a text box ready for the student to explain their thinking and strategy.
slideShot capture

Code It (Advanced, you might want to stop looking)

I had a lot of fun coding this puzzle. If you’re doing some coding and spreadsheets with your students you may want to challenge them to code their own. No cheating and looking at my code 🙂 However, no coding is required to use this puzzle! I already coded it. Even thinking about how they would code it, even if they couldn’t code it themselves.


Without coding, students can use simple spreadsheet formulas and conditional formatting to create a puzzle to share with a classmate to solve. =if(B2+C2+D2=E2,”Google Job”,”Try Again”)

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