1. How do you describe elevations that are above sea level and below sea level?

2. In this lesson you will learn how to use positive and negative numbers by thinking about situations with elevations.

3. Let’s Review Positive Numbers Negative Numbers 0 2 4 -2 -4 6 -6

4. A Common Mistake 200 feet below sea level -200 feet below sea level

5. Core Lesson Sea level is another way of referring to 0. 0’ -2’ 2’

6. Core Lesson 0’ 220’ 700’

7. Core Lesson -5’ or 5’ below sea level 0’ -5’ 3’

8. Core Lesson -400’ or 400’ below sea level 0’ -400’ 3’

9. Core Lesson Some places on land are actually below sea level! Death Valley in California is 282’ below sea level or –282’. –282’

10. In this lesson you learned how to use positive and negative numbers by thinking about situations with elevations.

11. Guided Practice 1. A hiker climbs 150 feet up Mt. Whitney. Is this a positive or negative number? 2. A submarine dives 200 feet below sea level. How would you write this?

12. Extension Activities Do a web search to find elevations for different parts of the country. What is the elevation where you live?

13. Do a web search to find the highest elevations in the world and the lowest. Where are most of the highest mountains located?

14. Do other planets have mountains? Pick a planet and research its elevations. How do these compare to earth’s?

15. Quick Quiz 1. Mt. Everest is 29,029 feet above sea level. Is this a positive or negative number? 2. If you go scuba diving and go 50 feet below sea level, how would you write the elevation?