LEARN NC

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

What balances?

http://illuminations.nctm.org/LessonDetail.aspx?ID=L119

A lesson plan for grade 2 Mathematics

Provider: National Council of Teachers of Mathematics


Learn more

Help

Please read our disclaimer for lesson plans.

Legal

This catalog record is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License. This license applies to the content of this page only and does not apply to the referenced website.

This lesson encourages students to explore another meaning of subtraction, the balance. They use subtraction facts to generate related addition facts and explore at the concrete level the idea of subtraction as the inverse of addition. Through a series of activities, the teacher demonstrates the concept of subtraction in mathematics.

Students will:

  • Model the balance meaning of subtraction.
  • Record subtraction modeled on the balance.

NCTM Standards and Expectations covered in this lesson include:

  • Counting with understanding and recognize “how many” in sets of objects.
  • Understanding various meanings of addition and subtraction of whole numbers and the relationship between the two operations.
  • Developing and using strategies for whole-number computations, with a focus on addition and subtraction.
  • Developing fluency with basic number combinations for addition and subtraction.

North Carolina Curriculum Alignment

Mathematics (2004)

Grade 2

  • Goal 1: Number and Operations - The learner will read, write, model, and compute with whole numbers through 999.
    • Objective 1.01: Develop number sense for whole numbers through 999.
      • Connect model, number word, and number using a variety of representations.
      • Read and write numbers.
      • Compare and order.
      • Rename.
      • Estimate.
      • Use a variety of models to build understanding of place value (ones, tens, hundreds).
    • Objective 1.03: Create, model, and solve problems that involve addition, subtraction, equal grouping, and division into halves, thirds, and fourths (record in fraction form).
    • Objective 1.04: Develop fluency with multi-digit addition and subtraction through 999 using multiple strategies.
      • Strategies for adding and subtracting numbers.
      • Estimation of sums and differences in appropriate situations.
      • Relationships between operations.
    • Objective 1.05: Create and solve problems using strategies such as modeling, composing and decomposing quantities, using doubles, and making tens and hundreds.