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Instructor Overview

In this lesson, students use an interactive map to compare the crowdedness of three countries of their choice. They learn that to compare countries with different areas and populations, they need to calculate population density—a rate that compares the population of a region to its area.

Key Concepts

A ratio is a comparison of two quantities by division. It can be expressed in the forms a to b, a:b, or ab, where b ≠ 0. The value of a ratio is found by dividing the two quantities. A ratio provides a relative comparison of two quantities. A rate is a ratio that compares two quantities measured in different units. Population density is a rate that compares the population of a region to its area. The value is given in number of people per unit of area.

ELL: Identifying key words are crucial for students. Spend some time discussing the key vocabulary in this unit.

Goals and Learning Objectives

  • Explore rate in the context of population density.
  • Compare three countries to see which is most crowded—that is, which has the greatest population density.