Overview | The Math | The Lesson

Activity Summary

Five volunteers form a Human Counting Machine. For each number from 0 to 31, this machine provides a secret code consisting of some (or all) of the numbers: 16, 8, 4, 2, 1.

Mathematical Goals

This activity reinforces the concept of a number as a quantity, rather than as the series of digits by which we represent it. It is a visual illustration of using a binary counting system. Children actually learn how to convert back and forth between decimal and binary expansions of numbers. Here, binary expansions are disguised as secret codes.

TEKS Content

111.14 (grade 2): 12B, 12C
111.15 (grade 3): 15B, 15C
111.16 (grade 4): 14B, 14C
111.17 (grade 5): 14B, 14C
111.22 (grade 6): 5, 11, 12, 13

Lesson Duration

45 minutes.

Materials

You will need:

• A secret code table per student (included in the lesson kit). Here is a completed table for your reference.
• Five large labels, one for each number: 1, 2, 4, 8, 16. These may be done out of paper or fabric.
• Tape.

Download the Lesson Kit (pdf) Continue to the Math