Math Journal: The 1-2-3 Puzzle

There’s still time to check out my Math Journaling Adventures project and discover how playful writing activities will help your students learn mathematics. Preorder your books today!

Meanwhile, here’s a math puzzle to share with your kids…

Write down any whole number. It can be a single-digit number, or as big as you like. For example:

64,861,287,124,425,928

Now, count up the number of even digits (including zeros), the number of odd digits, and the total number of digits your number contains. Write those counted numbers down in order, like this:

64,861,287,124,425,928
even 12, odd 5, total 17

Then, string those numbers together to make a new long number, like so:

12,517

Perform the same operation on this new number. Count the even digits, odd digits, and total length:

12,517
even 1, odd 4, total 5

And do it again:

145
even 1, odd 2, total 3

Can you find a number that doesn’t turn into 123?