This Instructional Activity is a part of the Lesson 16, Unit 4, Grade 6. This activity prompts students to make sense of and write equations for a variety of situations involving fractions and all four operations. After writing equations, students are assigned two problems to solve, at least one of which is a division problem. Before calculating, students first estimate their answer. Doing so helps them to attend to the meaning of the operation and to the reasonableness of their calculated answer in the context of the situation.