  # Surf for More Math

## Lesson 3 - Adding Integers Using the Zero Principle

Use these activities to encourage students to have fun on the Web while learning about adding integers using the zero principle. Students can try these activities on their own or in pairs.

### Goal

Use the zero principle, with and without models, to add integers.

### Builds Upon

Student Book pages 192-195

### Instructions for Use

Additive Inverse gives students a fundamental understanding of opposite integers and the zero principle.

To use Additive Inverse, read through the Web site and answer the questions using paper and pencil.

Opposite Integers lets students demonstrate concretely and pictorially that the sum of opposite integers is zero.

To use Opposite Integers, read the explanation for the sum of opposite integers and study the models. Then practice working with opposite integers using the thermometer applet.

The initial temperature displayed below the thermometer is 32 degrees F. Click on -10 three times, and -1 twice, to reduce the temperature by 32 degrees. The level of the liquid in the thermometer should show empty and the temperature displayed should be 0 degrees. Click on +10 and then on -10, the liquid level should be empty and the temperature should be 0 degrees. Try other combinations to demonstrate the sum of opposite integers is zero.   