The activities in this 6-lesson unit use fish-shaped crackers to help students develop their understanding of comparative subtraction by exploring five meanings of subtraction (counting, sets, number line, balance, and inverse of addition). Students investigate properties of subtraction, represent subtraction with objects and pictures, record subtraction with vertical notation and equations, create and solve problems, and carry out missing addend activities. Lessons include questions for student discussion and teacher reflection, extensions, printable student sheets, assessment options, and links to online applets.


  • Language Arts > General
  • 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


Grade 2,Grade 1,Make use of structure,NSDL,Addition,Early Elementary,Kindergarten,Music,Express regularity,Representation,Number concepts,Social Sciences,Arithmetic,Analyze and persevere,Concept formation,Process skills,Number and operations,Visual representation,Mathematical language,Word problems,Audio/Visual,Properties of operations,Model with mathematics,Subtraction,Life Science,Composition and decomposition of numbers,Whole numbers,Practice Standards,Vocational/Professional Development Education,NSDL_SetSpec_ncs-NSDL-COLLECTION-000-003-112-027,Comparison of numbers,oai:nsdl.org:2200/20140901103619753T,Elementary School,Language Arts,Modeling,Reason quantitatively,Chemistry,Operations,Education,Number sense,Algebraic representation,Mathematics,Connections,Engineering,Problem solving,Communication,Counting



Access Privileges:

Public - Available to anyone

License Deed:

Creative Commons Attribution Non-Commercial Share Alike


This resource has not yet been aligned.
Curriki Rating
'NR' - This resource has not been rated
'NR' - This resource has not been rated

This resource has not yet been reviewed.

Not Rated Yet.

Non-profit Tax ID # 203478467