Lesson 17

This warm-up prompts students to analyze and compare equations. In addition to calculating the value of each expression, students also think about the structure of each expression, including both the operations and the numbers. 

• Groups of 2
• Display the image.
• “Escojan una que sea diferente. Prepárense para compartir por qué es diferente” // “Pick one that doesn’t belong. Be ready to share why it doesn’t belong.”
• 1 minute: quiet think time

• “Discutan con su compañero cómo pensaron” // “Discuss your thinking with your partner.”
• 2–3 minutes: partner discussion
• Record responses.

• Display equations A and B.
• “¿En qué se parecen las ecuaciones?, ¿en qué son diferentes?” // “How are the equations the same? How are they different?” (They are related facts. They both have a total of 10 and 6 and 4 as parts. One is addition and one is subtraction.)

The purpose of this activity is for students to compare different story problems to determine how they are the same and different. The stories being compared represent problem types students have worked with in previous lessons, specifically:

• Add to, Change Unknown and Put Together, Addend Unknown
• Take From, Result Unknown and Take Apart, Addend Unknown

As students discuss the similarities of the story problems, they may notice the structures of the problems are connected, the same operations can be used to solve the problems, or that the answer is in the same place in the equation.

During the synthesis, students discuss a Put Together, Both Addends Unknown problem and consider how the structure of the problem is different from the others.

• Groups of 2
• “Piensen en los juegos que les gusta jugar cuando tenemos tiempo libre en la escuela. Pueden ser juegos que se juegan adentro o al aire libre” // "Think about games you like to play when we have free time at school. They can be indoor or outdoor games."
• 30 seconds: quiet think time
• Share responses and record in two categories, indoor games and outdoor games.

• “Con su compañero van a leer dos parejas de problemas-historia sobre juegos que los estudiantes juegan en la escuela. Van a pensar en qué se parecen y en qué son diferentes las parejas de problemas” // “You and your partner are going to read two pairs of story problems about games students play at school. You are going to think about how the pairs of story problems are the same and different.”
• Read the first two story problems to the class.
• 1 minute: quiet think time
• “Hablen con su compañero sobre lo que pensaron que era parecido y diferente en los dos problemas” // “Talk to your partner about how the two problems are the same and different.”
• 4 minutes: partner discussion
• Share responses.
• Repeat with the next two problems.

• Display “9 estudiantes están jugando mímica. Algunos representan deportes y algunos representan animales. ¿Cuántos estudiantes representan deportes? ¿Cuántos representan animales?” // “9 students are playing charades. Some students act out sports and some act out animals. How many students act out sports? How many act out animals?”
• “¿En qué se parece este problema a los otros?, ¿en qué es diferente?” // “How is this problem the same as the others? How is it different?” (It still has 9 as the total. This time, you don’t know either part.)

The purpose of this activity is for students to solve a story problem and write an equation to match it. Students are divided into nine groups and each group gets one of the story problem cards from the blackline master. Students individually solve the story problem and write an equation to match it before creating a poster with their group. During the synthesis, students explain how the equations match the story problem. When students recognize that the numbers in the equations represent specific quantities in the story problems, they reason abstractly and quantitatively (MP2).

• Create one set of Story Problem Cards from the blackline master.

• Groups of 2–4, so there are 9 groups
• Give each group tools for creating a visual display and one of the story problems.

• “Ahora resolveremos algunos problemas sobre juegos que los estudiantes juegan al aire libre” // "Now we will solve some problems about games students play outdoors."
• “Lean su problema con su compañero o en grupo. Después, resuelvan el problema de manera individual. Muestren cómo pensaron. Usen dibujos, números o palabras. Escriban una ecuación que corresponda al problema-historia” // “Read your problem with your partner or group. Then solve the problem on your own. Show your thinking using drawings, numbers, or words. Write an equation to match the story problem.”
• 4 minutes: independent work time
• “Trabajen con su compañero o en grupo para ponerse de acuerdo en la respuesta del problema-historia y crear una presentación visual de su trabajo. Si mostraron lo que pensaron de diferentes formas, inclúyanlas todas en el póster” // “Work with your partner or group to agree on the answer to the story problem and make a display of your work. If you showed your thinking in different ways, include them all on the poster.”
• 6 minutes: small-group work time
• Monitor for 2–3 posters in which the representation is clear, labeled, and has accurate equations.

• Display previously identified posters.
• “¿Cómo corresponde la ecuación que escribió cada grupo al problema-historia?” // “How does the equation each group wrote match the story problem?”