This Problem Set is a part of the Lesson 12, Unit 3, Grade 1. In this lesson, students interpret information presented in graphs by exploring "compare with difference unknown" problems. They begin with visualizing these problems in their easily accessible "equalizing" contexts by answering questions such as, "How many more students would Category A need in order to have the same amount as Category B?" Students use their understanding of comparing lengths from earlier lessons to compare the responses in three categories.
