Find My Card

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In this activity, learners find the answer to the question, "if you have a pile of 8 cards, and you remove half, then half again, how many times can you do this until you get to just one card?" This way of thinking about answering questions has led to a way of understanding how all data is represented on computers using the binary number system. This area of computer science is called "information theory", where we think about how to represent data using just two different values. This activity includes step-by-step instructions with pictures, an explanation of the computer science behind the game, and extensions.

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
5 to 10 minutes

Estimated Materials Cost:
1 cent - $1 per group of students

Age Range:
Ages 6 - 18

Resource Types:
Activity, Game


Materials List (per group of students)

  • At least 2 people
  • A pen or pencil
  • 8 small pieces of paper (you can cut a sheet into 8 parts)


  • Engineering and Technology
    • Computing
      • Computer Science
      • Information Systems
      • Information Technology

Informal Categories

  • Computers
  • Games


Components that are part of this resource:

Access Rights:

  • Free access


Source Collection

  • CS Unplugged At Home


Funding Sources:

  • University of Canterbury
  • Google
  • Microsoft