The purpose of this activity is for students to consider numbers that make sense in situations involving elapsed time. Then students solve the problems. While a variety of times and answers make sense for each situation, students focus on justifying why their choices make sense to them (MP3).

Consider preparing and displaying images of roller coasters and Ferris wheels for students who may be unfamiliar with carnival attractions.

• “What is the problem about?”
• “How long do you think it would make sense to wait in line (or wait for a friend, or go on rides without breaks)? What time do you think would make sense to arrive at the fair (or to be in line for a ride)?”

• Select 2–3 students to share the numbers they chose for each problem.
• As students share, ask:
  • “How did you decide what numbers (or times) to choose for each problem?”
• Ask the class:
  • “Why do these numbers (or times) make sense for this situation?”
  • “What numbers (or times) would not make sense in this situation?”

The purpose of this activity is for students to write a question that could be answered by given mathematical work and that would make sense in the given situation. When students interpret given student work in terms of the supplied information and decide what question the work might answer, they identify important quantities and their relationships in context (MP4).

• “What numbers from the work do you see in the information about the lemonade stand?”
• “What would the work represent in the lemonade stand situation? What question would lead up to this work?”

• For each problem, invite a group to read the question they wrote.
• Ask the class:
  • “How does their question make sense with this mathematical work and what we know about the situation?”
  • "What is the answer to their question? How do you know?"
• Consider asking:
  • “What did you like about writing the questions to match the mathematical work?”
  • “What was challenging about writing the questions to match the mathematical work?”