Overview | The Trick | The Lesson

Activity Summary

The trick starts with the audience picking a number for the magician to guess. The magician asks the crowd five yes or no questions and then successfully guesses the number. After that, the magician explains to the audience how to perform the trick. Once that's been revealed, the magician shows the students how to build their own magic kits.

Mathematical Goals

This trick reinforces the concept of a number as a quantity, rather than as the series of digits by which we represent it. By doing a "magic trick" and using a "secret code machine," children actually learn how to convert back and forth between decimal and binary expansions of numbers. Here, binary expansions are disguised as secret codes. This trick reinforces the concept of a number as a quantity, rather than as the series of digits by which we represent it. By doing a "magic trick" and using a "secret code machine," 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

Lesson Duration

45-90 minutes.

Materials

You will need:

• A large magic kit for the magician (included in the lesson kit)
  
  
  
  
• One secret code machine per student, made up of 5 small cups labeled 16, 8, 4, 2, and 1. (Tip: Small plastic bathroom cups labeled with permanent marker or stickers work well.)
  
  
  

  
  

• A secret code recording table (included in the lesson kit) for each student. Some of the entries in the table are shown below:

• (Refer to this completed table for a full list of entries.)

  
  

• A bag containing 31 small items per student. (Tip: Dry beans work well.)

  
  

• A set of 5 blank cards per student (included in the lesson kit). (Tip: Simple construction paper and scissors will also work.)

Download the Lesson Kit (pdf) Continue to the Trick