Binary Numbers

The binary number system plays a central role in how information of all kinds is stored on computers. Understanding binary can lift a lot of the mystery from computers, because at a fundamental level they’re really just machines for flipping binary digits on and off. There are several activities on binary numbers in this document, all simple enough that they can be used to teach the binary system to anyone who can count! Generally children learn the binary system very quickly using this approach, but we find that many adults are also excited when they finally understand what bits and bytes really are.

Flipping cards

Activity description (PDF)

Translations and other versions:



  • Tim demonstrates how binary numbers are stored.

Related Resources

  • An older version of this activity can be downloaded in PDF format here. The content is similar to the current version, but there’s some extra technical information.

Curriculum Links

Great Principles of Computer Science [info]
  • Recollection
ACM K12 Curriculum [info]
  • Level I (Grades K–2) Topic 11: Understand how 0s and 1s can be used to represent information, such as digital images and numbers.
New Zealand Curriculum [info]
    • Mathematics Level 2: Position and orientation
        • Find rules for the next member in a sequential pattern.
      • Generalise that whole numbers can be partitioned in many ways.
    • Mathematics Level 3: Patterns and relationships
        • Connect members of sequential patterns with their ordinal position and use tables, graphs, and diagrams to find relationships between successive elements of number and spatial patterns.
      • Generalise the properties of addition and subtraction with whole numbers.
  • Technology Level 3: Technological systems
    • Understand that technological systems are represented by symbolic language tools and understand the role played by the “black box” in technological systems.