Here’s one more entry for my 20+ Things to Do with a Hundred Chart post, thanks to David Radcliffe in the comments on Monday’s post:
(30) Can you mark ten squares Sudoku-style, so that no two squares share the same row or column? Add up the numbers to get your score. Then try to find a different set of ten Sudoku-style squares. What do you notice? What do you wonder?
[Suggested by David Radcliffe.]
Share Your Ideas
Can you think of anything else we might do with a hundred chart? Add your ideas in the Comments section below, and I’ll add the best ones to our master list.
Denise Gaskins' Let's Play Math 
I love this a lot! However, I think it might be easier to figure out what’s going on with a 0-99 square, rather than 1-100.
Perhaps it would. I get so used to using the hundred chart that starts at 1 that I forget about the other style.
Both The Math Worksheet Site and Helping With Math offer free downloads of either type of chart.