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Lesson Seeds: The lesson seeds are ideas for the indicator/objective that can be used to build a lesson. Lesson seeds are not meant to be all-inclusive, nor are they substitutes for instruction.

Standard 1.0 Knowledge of Algebra, Patterns, and Functions

Topic B. Expressions, Equations, and Inequalities

Indicator 2. Identify, write, solve, and apply equations and inequalities

Objective b. Find the unknown in an equation with one operation

Assessment limit: Use multiplication (×) and whole numbers (0-81)

Materials needed

Graphic representation of a balance pan

Activities

  • Begin by representing equations with a graphic of a two-pan balance, like the one below:

    balance

    Write several expressions for a number such as 12. Possible expressions could be:
    14-2, 8+4, 6+6, 36÷3, 4×3. Place two of the representations on the pans to show they are equal.

    balance

    Describe what would happen if they were not equal like the example below.

    balance

  • Have students fill in missing numbers to keep the two-pan balance level (equal).

    balance

    As they fill in the two-pan balance graphic, ask them to write the equation:
    8 = square + 3, square =5.

  • Continue to explore equations with single operations, including multiplication.

    balance

  • Write the equation that matches the balance:
    4 × square = 8       square = 2

For more activities, see "Balancing Act: The Truth Behind the Equals Sign" in the September issue of Teaching Children Mathematics from National Council of Teachers of Mathematics (NCTM), 2004.
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