This Instructional Activity is a part of the Lesson 5, Unit 9, Grade 7. In this activity, students make sense of what it means to say there are 42.3 people per square kilometer in some location. This activity gives some information about New York City and Los Angeles and ultimately asks students to decide which city is more crowded. Students may benefit from a demonstration of situations that feel more crowded vs. less crowded. In the data for this task, people are given in "blocks" of 1000 people. It's perfectly fine to make up a new unit customized to the situation, even if it doesn't have an o'cial name.