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.

• Select 2–3 students to share the numbers they chose for each problem.
• As students share, ask:
  • “¿Cómo decidieron qué números (o tiempos) escoger para cada problema?” // “How did you decide what numbers (or times) to choose for each problem?”
• Ask the class:
  • “¿Por qué estos números (o tiempos) tienen sentido en esta situación?” // “Why do these numbers (or times) make sense for this situation?”
  • “¿Qué números (o tiempos) no tendrían sentido en esta situación?” // “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).

• “¿Qué números del trabajo matemático ves en la información del puesto de limonada?” // “What numbers from the work do you see in the information about the lemonade stand?”
• “¿Qué representa el trabajo matemático en la situación del puesto de limonada? ¿Qué pregunta llevaría a este trabajo?” // “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:
  • “¿Por qué la pregunta que ellos hicieron tiene sentido teniendo en cuenta este trabajo matemático y lo que sabemos acerca de la situación?” // “How does their question make sense with this mathematical work and what we know about the situation?”
  • “¿Cuál es la respuesta a su pregunta? ¿Cómo lo saben?” //"What is the answer to their question? How do you know?"
• Consider asking:
  • “¿Qué les gustó de escribir preguntas que correspondieran al trabajo matemático?” // “What did you like about writing the questions to match the mathematical work?”
  • “¿Qué fue retador cuando escribieron las preguntas que correspondían al trabajo matemático?” // “What was challenging about writing the questions to match the mathematical work?”