Resources and Tools for Elementary Math Specialists and Teachers
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7 and Happy Numbers - Numberphile

In this 1.5-minute video, mathematician Dr Ria Symonds describes a characteristic of numbers such as 7, which after repeated squaring of digits and summing of the squares, result in the number 1, the first natural number. This introduction invites an investigation to find other "happy" numbers, and to find out what happens to "sad" numbers.
Contributed by: Brady Haran - Graphical designer, Numberphile - Publisher, Dr Ria Symonds - Author
This resource is included in the following PD Collection(s):
CCSS Practice Standard 8The resources in this collection are intended to help educators understand and implement the eighth Mathematical Practice Standard of the CCSS. You will find informative presentations, lesson plans, and problem sets that will help establish mathematical habits of mind that support this standard. You'll also find many problem tasks for use with students in the companion classroom collection.
Math TopicNumber Sense, Basic Operations, Number Concepts, Algebraic Thinking, Mathematical Practices, Mathematical Processes
Grade Level3, 4, 5
Resource TypeActivity, Video

  • Additional Information
    • AudienceLearner
    • LanguageEnglish (United Kingdom)
    • Education Topic
    • Interdisciplinary Connection
    • Professional DevelopmentNo
    • ContributorBrady Haran - Graphical designer, Numberphile - Publisher, Dr Ria Symonds - Author
    • Publication Date2012-02-10
    • RightsCopyright Numberphile
    • AccessFree access
  • Standards
    • Common Core State Standards for Mathematics

      Select a standards document:

  • User Comments
    • 4
      waiting for part 2
      By Uncle Bob on 04/16/2013 - 15:02
    • A brief intro to an intriguing investigation. A low threshold / high ceiling activity that can introduce the concepts of orbits and fixed points. Lots of arithmetic practice that serves a bigger purpose. By all means, see what happens to unhappy numbers.