Overview | The Math | The Lesson

The Lesson

1. Build the Human Counting Machine
2. Illustrate Counting with the Human Machine
3. Fill in the Secret Code Table
4. Extension (optional)

Build the Human Counting Machine

1. Ask for five volunteers to be part of a "human counting machine".
2. Write the numbers 1, 2, 4, 8, and 16 on sheets of paper to make five labels for the components of the machine. Have each volunteer tape one of these labels to his or her right arm so that it is visible to the class.
3. Arrange the five volunteers at the front of the classroom standing one arm's-length apart, so that their numbers are in descending order from left to right (as viewed by the rest of the class).

   
   
   

4. Explain the rules for being part of the counting machine (as described in The Math page).

Illustrate Counting with the Human Counting Machine

1. Pick a couple of numbers to feed into the machine.
2. Take the role of the machine operator. Show to the class how the machine works and how to read off the secret codes from the final positions.

Fill in the Secret Code Table

1. Distribute the secret code table.
2. Tap component 1's shoulder once. Ask the class to identify the secret code and write it down in their tables.
3. Keep the final position for 1 and tap a second time to get the secret code for 2.
4. Keep going one tap at a time until the class discovers and records in the table all the codes for numbers up to 31. At some point you may ask for new volunteers for the machine's components and operator.

Extension

The secret codes used in "Guess the Number" Magic Trick are the same codes found with The Human Counting Machine. What is different is the way to find the codes. You may therefore modify the "Guess the Number" Magic Trick lesson for use as an application of the Human Counting Machine lesson.

Download the Lesson Kit (pdf)