# Hot Air Balloon

## Opening

# Hot Air Balloon

The Hot Air Balloon interactive can be used to model addition of integers. In the simulation, positive integers are represented by heating the air and negative integers are represented by weight.

For example, to model adding −4 + 9, start at 0, add 4 units of weight, and then add 9 units of heat.

Use the Hot Air Balloon interactive to model each problem and find the sum. Write your answer as an equation.

- −4 + 9
- 7 + (−7)
- −3 + (−6)
- 2 + 8

INTERACTIVE: Hot Air Balloon