Before you get to the freebie, I have to ask you very kindly to please stop by the Best of the Web and check us out! We were recently very humbled to be featured alongside some amazing other blogs. What a cool site! I had a great time looking through all the other editions of 'Best of the Web' and finding some very cool new blogs to follow.
This was an idea I just HAD to get out of my head today.... you can download it for FREE from Google Docs HERE
It is a little activity to help your studensts think about numbers. You could use it with a wide range of student abilities, as it is open-ended and students can write a number of their choice (amke sur ethey are working alongside someone of similar ability).
I hope your students have fun with Secret Number!