Resources and Tools for Elementary Math Specialists and Teachers
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Circle 99

This interactive Java applet develops logical reasoning skills and fluency with two-digit addition. The game board consists of a ring of seven overlapping circles, each with 3 regions. Numbers are provided in five regions. The player drags 9 other numbers to the empty regions so that the sum of the numbers within each circle is 99.
Contributed by: National Library of Virtual Manipulatives, Publisher
Math TopicNumber Sense, Basic Operations, Number Concepts, Mathematical Practices, Mathematical Processes
Grade Level2, 3, 4, 5
Resource TypeActivity, Game, Interactive Media

  • Additional Information
    • AudienceLearner
    • LanguageEnglish (USA)
    • Education Topic
    • Interdisciplinary Connection
    • Professional DevelopmentNo
    • ContributorNational Library of Virtual Manipulatives, Publisher
    • Publication Date1999
    • Rights(c) 1999-2010 Utah State University
    • AccessAvailable for purchase, Free access
  • Standards
    • Common Core State Standards for Mathematics

      Select a standards document:

  • User Comments
    • 4
      Challenging puzzle
      By Uncle Bob on 11/13/2012 - 14:06
    • Very challenging for the student that hasn't done magic sum type puzzles with smaller numbers. Even so, once the student is committed this will deliver lots of 2-digit sums practice and should encourage and develop mental math skill. Several puzzles available as well as notes for the parent/teacher, and background for the student.