Thursday, April 9, 2009

KenKen Math: Engaging Operations

I love to teach math to my 4th graders; they really excel with numbers. Plotting coordinates, finding the circumference of a circle, multiplying decimals- they love it all. Still, when I test my students I can still find cracks in their fundamental number sense. They can still slip up with their
basic operations. What is an engaging activity that builds this core skill?

Remember Sudoku? Well, KenKen is a math puzzle that uses the framework of Sudoku but involves the four basic math operations. Rather than decipher which of 9 digits to put in a row, column, or box, in KenKen you are given an answer to a problem, such as 2-. This means that the two numbers in the box need to have a difference of two. Other boxes could hold three or more digits, and have an answer like 24x, meaning that the three digits multiplied euqal 24. However, like Sudoku, the row and column of the grid can only have one of each digit- but the gird can vary form a 4x4, 5x5, or higher.

I had my students solve a few puzzles, but the real thinking began when they had to create their own. They start by filling in a gird with a pattern of numbers, where they do not repeat in each column and row, and then they box off the digits and create problems using the four operations.
The students quizzed each other, and generally had an totally engaed computaton fest.

Try a few KenKen websites:

KenKen creator site (may not work from district computers- not sure why!)

New York Times KenKen and learning website

Here are some student-created examples, as well as a Smartboard template we used.


Jeff Lewis said...

There must be some cracks in my fundamental number sense because it took me 3 reads to figure out KenKen. I get it now, and I think this is really cool. I like any math activity that challenges kids to write problems rather than just solve them. Thanks for this. I am going to try it with my fourth graders.

Brian said...

KenKen rocks. I've made a video about how to start solving a 9x9 KenKen in which the operation signs are not given.

You can check it out at:

Have fun!