This problem with multiple solutions provides an opportunity for students to practice subtraction while developing logical thinking and systematic record-keeping strategies. Given a pyramid of six circles, solvers are challenged to arrange the numbers 1 - 6 so that each number is the difference between the two numbers just below it. Children may use pencil and paper or the interactive Flash applet provided. The Teachers' Notes page offers suggestions for implementation, discussion questions, ideas for extension and support, work sheets (pdf), and a link to a more challenging version.


  • Mathematics > General
  • Education > General

Education Levels:

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Grade 2,Grade 3,Grade 1,NSDL,Critical thinking,oai:nsdl.org:2200/20140728161021176T,Early Elementary,Visual representation,Strategies,Number concepts,Social Sciences,Arithmetic,Analyze and persevere,Process skills,Number and operations,Upper Elementary,Mathematical language,Subtraction,Informal Education,Whole numbers,NSDL_SetSpec_ncs-NSDL-COLLECTION-000-003-112-027,Practice Standards,Elementary School,Representation,Operations,Mental calculation,Communication,Mathematics,Reason quantitatively,Problem solving,Education,Construct arguments,Reasoning



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