Lesson 4.5 Integers

# The Coordinate Grid

#### Materials

• CCB Mathematics pages 124 - 129

#### Standards

• MP.1

• Apply and extend previous understandings of numbers to the system of rational numbers.

#### Objectives

• Plot and identify points on a coordinate grid

#### Key Concept

• Coordinate grids are a method of locating points in the plane by means of directions and numbers

#### Vocabulary

Tier 2 Origin Coordinate GridPerpendicular LinesX-AxisY-AxisX-CoordinateY-Coordinate Grid

## Before Lesson

Students will learn about the coordinate grid and how to identify and plot points using ordered pairs. To determine readiness, have students draw and label horizontal and vertical number lines that display both positive and negative integers.

## Background

Gather some examples of maps that use coordinate grids, or print sample maps from an online search. Show the examples to students, and encourage them to figure out the purpose of the lines that run north and south and east and west. Explain to students that those arrangements of lines form a coordinate grid. By finding where horizontal and vertical lines intersect, they can locate specific features or locations.

## Guided Practice

• The Coordinate Plane

## Core Skill

Interpret Data Displays: Allow students time to read the sidebar. Then give partners graph paper to complete the activity. If any groups are struggling, provide remediation by reviewing how to draw the axes, which axis is which, and how to locate points and write ordered pairs. Or you may wait to assign this activity until students have worked through Examples 1 through 3.

Make Sense of Problems: Read the sidebar as a class. Ask students questions as they draw a coordinate grid to match the problem: Which axis represents east to west? Which axis represents north to south? Label the directions. In terms of the grid, how can you represent one mile in your drawing?

## Extension

Describe a Coordinate Grid: Have students refer to the vocabulary words. Then invite students to select a coordinate grid from the lesson and use the vocabulary words to describe its parts.

Investigate Descartes: Have students research Descartes, inventor of the Cartesian plane. After reading about his life and work in mathematics, have students write one or two questions about Descartes’ work that they would like to answer through further research. Afterward, ask students to share their research in a digital presentation.