This Problem Set is a part of the Lesson 2, Unit 3, Grade 6. Students use positive and negative numbers to indicate a change (gain or loss) in elevation with a fixed reference point, temperature, and the balance in a bank account. Students use vocabulary precisely when describing and representing situations involving integers; for example, an elevation of -10 feet is the same as 10 feet below the fixed reference point. Students choose an appropriate scale for the number line when given a set of positive and negative numbers to graph.