Here’s a new entry for my 20+ Things to Do with a Hundred Chart post:
(29) Blank 100 Grid Number Investigations: Challenge your students to deduce the secret behind each pattern of shaded squares. Then have them make up pattern puzzles of their own.
[Created by Stuart Kay. Free registration required to download pdf printable.]
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 
We use number charts for multiplication tables to see the patterns.. http://arithmeticvillage.com/tina-times-activities.html
Multiplication patterns are very interesting! It can be fun to color several of them on one chart, too, to see which numbers show up the most.
Circle 10 numbers in the hundred chart, but do not pick two numbers in the same row or the same column. Add up the numbers that are circled. Do you always get the same answer?
That sounds like a fun “What Do You Notice?” puzzle! I’ll add it to the list, too.
I like the idea of ‘what do you notice’ puzzles. I’m reading An Elephant in the Classroom at the moment and the author says frequently about the importance of getting the children to see the maths for themselves. This is so counter to what we are taught in schools and yet I can see it really works! Thanks again for all your great ideas!