What's Missing?

Learning Resource Type

Learning Activity

Subject Area

Mathematics

Grade(s)

3

Overview

In this activity, students will practice finding the perimeter of rectangles and rectilinear shapes that have missing lengths. This activity includes a set of 18 task cards and a recording sheet.

Phase

After/Explain/Elaborate
Mathematics (2019) Grade(s): 3

MA19.3.25

Solve real-world problems involving perimeters of polygons, including finding the perimeter given the side lengths and finding an unknown side length of rectangles.

UP:MA19.3.25

Vocabulary

  • Attribute
  • Dimension
  • Perimeter
  • Polygon
  • Two-dimensional

Knowledge

Students know:
  • Measurable attributes of objects, specifically perimeter.
  • Strategies for modeling measurement problems involving perimeter.
  • Strategies for representing and computing perimeter.

Skills

The Students are able to:
  • Solve real-world and mathematical problems involving perimeters of polygons.
  • Find the perimeter of a figure given the side lengths.
  • Find an unknown side length of a polygon given the perimeter and one missing side length.

Understanding

Students understand that:
  • Perimeter is measured in length units and is the distance around a two-dimensional figure.
  • If all the sides of a polygon are equal, then the perimeter can be determined by multiplying one side length by the total number of sides.

Learning Objectives

The students will be able to solve real-world problems involving finding the perimeter of polygons.

The students will be able to find the unknown side of a polygon when given the perimeter.

Activity Details

The teacher will copy the task cards and recording sheet from the file What's Missing? The teacher will display the 18 task cards throughout the classroom. The students will visit each card, determine the missing length, solve for the perimeter of each shape, and move to the next card. The students will record their answers on the recording sheet before moving to the next card. The teacher will review the answers to the task cards at the end of the activity.

Assessment Strategies

The teacher will observe student responses to determine student understanding of the concept and skill. The teacher can use the following guidelines to ensure students meet the learning objective.

Check that the student:

  1. can correctly determine the missing length.
  2. can correctly solve for the perimeter of each shape.

Variation Tips

These cards can be used as quick images for an engage activity or can be used in small group for remediation.

Background / Preparation

The teacher will need to copy the cards and display them throughout the room. Each student will need a recording sheet, clipboard, and pencil. The teacher will need to determine how he/she wants to have the students move from card to card.

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