In this lesson, students review what they learned previously about positive and negative numbers. They remember that negative numbers are less than 0 degrees, while positive numbers are greater than 0 degrees. First, students look at thermometers, reading temperatures above and below zero and comparing them. Next, they examine the vertical position of animals above or below sea level and describe the vertical distances between them. Both activities involve a number line that is oriented vertically to help students make sense of the context. As students relate the relative position of numbers on the number line to the meaning of “above zero” and “below zero” in each context, they are reasoning abstractly and quantitatively (MP2).

The last activity is optional because it provides an opportunity for additional practice comparing and ordering a set of rational numbers that includes fractions.