2.G.A.2

Partition a rectangle into rows and columns of same-size squares and count to find the total number of them.

 

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Unpacking the Standard: 2.G.A.2
Student Friendly Learning Target: 2.G.A.2

Summary:

This standard begins the formal foundation of the idea of area development. Since we measure area in square units, it is natural to begin with rectangles and partition them into square regions so that we can easily count the total.


Understanding the Standard:

    • Have students finish partitioning a rectangular cake that has already been divided into equal rows.
    • Have students draw a picture to show how one could cut a cake into square pieces.
    • Heavy use of pictures will facilitate student understanding of this standard.
    • The use of graph paper should make the task of partitioning a rectangle easier and allow for students to see the idea without getting bogged down in detailed measurement.

      Questions to Focus Instruction:

        • Can students find the total number of squares on a checkerboard and then use the checkerboard as a pattern to divide a different sized square into a grid of squares and count the total number?
        • Can students use graph paper to represent the same rectangle as being composed of many short rows as well as a few long columns?
        • Can students use unifix cubes to create rectangular prisms and then determine through skip counting how many unifix cubes were used?

        Skills

        Prior to: In first grade, students began measuring using iterated units. (See 1.MD.A.2).  They should also be familiar with the grade-level work of using rectangular arrays of 5 (see 2.OA.C.4), and with composing and decomposing shapes.

        At Grade Level:
        Students are beginning to construct the idea of area.

        Moving Beyond:
        Students will partition shapes, including rectangles into equal parts. They will then express each section as a fraction of the whole rectangle.  Go to 3.G.A.2 to see the progression of related skills.