This problem provides an opportunity for students to form and test conjectures, and make generalizations, while exploring the effect of parity on simple whole number sums. Solvers are asked to arrange given sets of numbers in a V formation so that the sums of the numbers in each "arm" are equal. The Teachers' Notes page offers suggestions for implementation, discussion questions, ideas for extension and support, a printable record sheet (pdf) and links to two YouTube videos demonstrating use of the problem in a professional development setting (videos cataloged separately).


  • Mathematics > General
  • Education > General

Education Levels:

  • Grade 1
  • Grade 2
  • Grade 3
  • Grade 4
  • Grade 5
  • Grade 6
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Grade 2,Grade 3,NSDL,Grade 4,Grade 5,Addition,Early Elementary,Visual representation,Strategies,Number concepts,Arithmetic,Analyze and persevere,Concept formation,Process skills,Number and operations,Upper Elementary,Algebra,Critical thinking,Subtraction,Life Science,Composition and decomposition of numbers,Patterns and sequences,Informal Education,Whole numbers,oai:nsdl.org:2200/20140728160751916T,NSDL_SetSpec_ncs-NSDL-COLLECTION-000-003-112-027,Practice Standards,Elementary School,Number patterns,Reason quantitatively,Algebraic thinking,Chemistry,Operations,Parity,Communication,Mathematical language,Mathematics,Problem solving,Education,Construct arguments,Reasoning,Representation



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