This second Mystery Sums Sketchpad activity, which opens on Geometer's Sketchpad as well as on iOS with Sketchbook Explorer (cataloged separately), allows learners to use logic and early algebra reasoning skills to find the secret numerical value from -10 to 10 of the letters, A, B, -B and C. Players drag any two letters across a divider to the right to reveal their sum. Students can play the game multiple times, with the computer generating new random values, or they can create challenges for each other to solve. A movie provides detailed instructions and downloadable PDF of teacher notes and student worksheets are also included.


  • Mathematics > General
  • Education > General

Education Levels:

  • Grade 1
  • Grade 2
  • Grade 3
  • Grade 4
  • Grade 5
  • Grade 6
  • Grade 7
  • Grade 8
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Grade 6,NSDL,Grade 4,Grade 5,Addition,Express regularity,Representation,Number concepts,Social Sciences,Arithmetic,Analyze and persevere,Process skills,Number and operations,Visual representation,Algebra,oai:nsdl.org:2200/20140728160742805T,Subtraction,Life Science,Composition and decomposition of numbers,Informal Education,Whole numbers,Middle School,Vocational/Professional Development Education,NSDL_SetSpec_ncs-NSDL-COLLECTION-000-003-112-027,Practice Standards,Deductive reasoning,Elementary School,Reason quantitatively,Algebraic thinking,Chemistry,Operations,Mental calculation,Upper Elementary,Mathematics,Connections,Problem solving,Education,Reasoning



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