Task# Mile High

Illustrative MathematicsVaries

The first two parts of this task ask students to interpret the meaning of signed numbers and reason based on that meaning in a context where the meaning of zero is already given by convention. In 7th grade, students will be asked to connect this reasoning to finding the difference of signed numbers, but they are not expected to know how to add and subtract signed numbers in 6th grade. The third part is meant as a discussion point about what, exactly, 'sea level' means, and will require teachers either to supply more information about the meaning of sea level or to encourage students to research this. Since the oceans have tides, sea level is defined to be the average height of the ocean surface (and is technically called mean sea level).