This Sketchpad activity, which opens on Geometer's Sketchpad and on iOS with Sketchbook Explorer (cataloged separately), allows players to learn about the use of symbols and variables as a way to represent numbers as students solve puzzles involving two unknowns using algebraic thinking. The sketch displays eight rows of symbols and each row presents a different combination of squares and circles. When students drag a row of symbols across the vertical divider line, the sketch displays the sum of the symbols. By dragging two or more rows, students gather information and determine the value of the circle and the square. Overview instructions and teacher notes are available as downloadable PDF.


  • Mathematics > General
  • Education > General

Education Levels:

  • Grade 1
  • Grade 2
  • Grade 3
  • Grade 4
  • Grade 5
  • Grade 6
  • Grade 7
  • Grade 8
  • Grade 9
  • Grade 10
  • Grade 11
  • Grade 12


Visualization,NSDL,Grade 4,Grade 5,Addition,Express regularity,Reason quantitatively,Number concepts,Social Sciences,Arithmetic,Analyze and persevere,Concept formation,Process skills,Number and operations,oai:nsdl.org:2200/20140728161022337T,Visual representation,Algebra,Subtraction,Equations,Informal Education,Whole numbers,Vocational/Professional Development Education,NSDL_SetSpec_ncs-NSDL-COLLECTION-000-003-112-027,Practice Standards,Deductive reasoning,Elementary School,Strategies,Algebraic thinking,Operations,Mental calculation,Upper Elementary,Mathematics,Connections,Problem solving,Education,Reasoning,Representation



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