LEARN NC

K–12 teaching and learning · from the UNC School of Education

About this resource

Appropriate grades
6–8
Subjects
mathematics (algebra, geometry)
Provider
National Council of Teachers of Mathematics

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In this lesson, students use a plus sign to explore the concepts of identity, inverse, commutativity, and associativity.

Students will:

  • Determine the identity element for a geometric operation.
  • Decide if there is an inverse for each move.
  • Determine if the operation is commutative or associative.

Illuminations provides handouts for completing the activity.

This lesson follows NCTM Standards and Expectations that teach students how to:

  • Relate and compare different forms of representation for a relationship.
  • Represent, analyze, and generalize a variety of patterns with tables, graphs, words, and, when possible, symbolic rules.
  • Use geometric models to represent and explain numerical and algebraic relationships.

North Carolina Curriculum Alignment

Mathematics (2004)

Grade 6

  • Goal 3: Geometry -The learner will understand and use properties and relationships of geometric figures in the coordinate plane.
    • Objective 3.01: Identify and describe the intersection of figures in a plane.
    • Objective 3.03: Transform figures in the coordinate plane and describe the transformation.
    • Objective 3.04: Solve problems involving geometric figures in the coordinate plane.
  • Goal 5: Algebra - The learner will demonstrate an understanding of simple algebraic expressions.
    • Objective 5.01: Simplify algebraic expressions and verify the results using the basic properties of rational numbers.
      • Identity.
      • Commutative.
      • Associative.
      • Distributive.
      • Order of operations.
    • Objective 5.02: Use and evaluate algebraic expressions.
    • Objective 5.04: Use graphs, tables, and symbols to model and solve problems involving rates of change and ratios.

Grade 7

  • Goal 3: Geometry - The learner will understand and use properties and relationships in geometry.
    • Objective 3.01: Using three-dimensional figures:
      • Identify, describe, and draw from various views (top, side, front, corner).
      • Build from various views.
      • Describe cross-sectional views.
  • Goal 5: Algebra - The learner will demonstrate an understanding of linear relations and fundamental algebraic concepts.
    • Objective 5.03: Use and evaluate algebraic expressions, linear equations or inequalities to solve problems.
    • Objective 5.04: Develop fluency in the use of formulas to solve problems.

Grade 8

  • Goal 3: Geometry - The learner will understand and use properties and relationships in geometry.
  • Goal 5: Algebra - The learner will understand and use linear relations and functions.
    • Objective 5.04: Solve equations using the inverse relationships of addition and subtraction, multiplication and division, squares and square roots, and cubes and cube roots.