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# Perimeter Activity

## Materials

• Square inch grids, page 109 (1 per student)

• Perimeter grids, page 110 (1 per student)

• Crayons (2 colors per student)

• Scissors (1 per student)

• 12" x 18" construction paper (1 sheet per student)

• Glue sticks (1 per student)

• The completed project prepared by the teacher before the lesson

## Introduction

The purpose of this project is to teach students how to find the perimeter of complex shapes. To do this, students will surround shapes with linear units (inches), which they will paste one at a time.

This method of finding perimeter is based on the theory that students struggle with non-linear measurement (i.e. measurement around corners) because they fail to understand “iterations” of unit measurement. In other words, they don’t recognize that bending a four-inch line has no effect on the line’s measured length. This lesson teaches them that four iterations of an inch, regardless of each inch’s direction, is what determines a four inch line.

# Area Activity

## Materials

• Area sheets, page 111 (1 per student)

• Crayons (2 colors per student)

• Scissors (1 per student)

• Background sheets, page 112 (1 per student)

• Glue sticks (1 per student)

• The completed project prepared by the teacher before the lesson

## Introduction

This lesson teaches students to determine the area of unusual shapes (shapes other than basic squares and rectangles). It also requires them to make symmetrical patterns.

The lesson is designed, in part, to provide an alternative to the often used, but problematic way of teaching the difference between area and perimeter. Sometimes, teachers will say, “When finding perimeter, we add; when finding area, we multiply.” If this explanation becomes the basis for understanding area and perimeter, students are sure to be stumped on more difficult problems involving these concepts.

Perimeter needs to be understood for what it really is: the repetition of linear units around shapes (see Perimeter lesson, page 32). Likewise, area needs to be understood as the repetition of square units over the surface of a shape. Furthermore, students should recognize that if a surface’s square units are rearranged or broken apart, the area of the surface does not change.

The Math Art area lesson allows students to create complex shapes one square inch and one half-square inch at a time. This allows them to find area by simply counting wholes and halves. Gaining such a fundamental understanding of area will better prepare students for future lessons that teach multiplication as another method of finding area.