Binary Numbers

- numbers that use only two digits: zero and one.

The way I got interested in this subject was from a "mind reading" trick that a few teachers showed me.
First I learned the trick.
Then I explored how it worked.
In the process I invented another trick - the paper computer.
For you teachers who may be peeking in on this kid's site, I also have an activity with Cuisenaire rods that illustrate how place value works in a two-digit number system.
I first started on this project when I worked at the Maryland Science Center as they were developing their Beyond Numbers Math Exhibit. It was first meant to be used as an "explainer"  - something that roving presenters would show museum visitors. That explainer is described here.

Here's the menu for this site.

The "mind reading" trick (- it's been repaired so it works now!)
How the "mind reading" trick is done
The paper computer (how it does the "mind reading" trick)
Place value (why the trick works)
Disks to download for the trick
Cards to download for the computer
Cuisenaire worksheet to download on legal size paper