# Activities

• • • ##### Subject Area

• Math: PreAlgebra: Number Sense and Operations

• ##### Author 6-8

60 Minutes

• ##### Device
• TI-73 Explorer™
• ##### Other Materials
This is Activity 1 from the EXPLORATIONS Book:
Walking the Line: Activities for the TI-73 Number Line.

## Integers! It All Adds Up!

#### Activity Overview

In this activity, students will use the number line to add integers and to justify and support the rules they develop.

#### Before the Activity

• Set up the calculator as explained in the activity
• See the attached PDF file for detailed instructions for this activity
• Print pages 6 - 11 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Use the NUMLINE application and select the number line option that represents the operation of addition
• Add two positive integers and observe vectors of the number line
• Observe that the sum moves to the right
• Predict the vector sketch for addition of zero and a negative integer
• Use the calculator and verify the sketch
• Add two negative integers and observe the vectors
• Understand that addition of negative numbers moves the vectors in the negative direction
• Add a positive and negative integer, sketch the prediction and verify using the calculator
• Observe that the vectors for addition of positive and negative integers point in opposite directions
• #### After the Activity

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary