Lesson 15

The purpose of this Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information. 

• Groups of 2
• Display the image.
• “¿Qué estimación sería muy alta?, ¿muy baja?, ¿razonable?” // “What is an estimate that’s too high?” “Too low?” “About right?”
• 1 minute: quiet think time

• “Discutan con su compañero lo que pensaron” // “Discuss your thinking with your partner.”
• 1 minute: partner discussion

• “¿Alguien hizo una estimación menor que 20? ¿Alguien hizo una estimación mayor que 30?” // “Is anyone’s estimate less than 20? Is anyone’s estimate greater than 30?”
• “Teniendo en cuenta esta discusión, ¿alguien quiere ajustar su estimación?” // “Based on this discussion does anyone want to revise their estimate?”

The purpose of this activity is to solve Compare story problems with unknowns in all positions, Add To, Start Unknown problems, and Take From, Start Unknown problems. Students show their thinking in any way they choose including drawings, numbers, words, or equations (MP2).

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.
• “Otra manualidad que muchas personas disfrutan es el origami. Origami es el arte de doblar papel. Hay muchas cosas distintas que pueden hacer con papel. Van a resolver algunos problemas sobre el origami que Clare y sus compañeros hicieron en clase” // “Another craft that lots of people enjoy is origami. Origami is the art of folding paper. There are lots of different things you can make. You are going to solve some problems about origami that Clare and her classmates made.”

• Read the task statement.
• 8 minutes: partner work time

• “Ahora van a crear pósteres que muestren su trabajo y luego harán un recorrido por el salón” // “Now, you will make posters of your work and do a gallery walk.”

The purpose of this activity is for students to analyze the work of their classmates and write equations to show how they made sense of each others' thinking. During the synthesis, students discuss how different representations and equations can match the same story problem. When students share connections between different representations and the story problems, they reason abstractly and quantitatively (MP2).

• Groups of 2
• Give each group tools for creating a visual display.
• Assign each group a problem from the previous activity.

• “Con su compañero, creen una presentación visual que muestre cómo pensaron en el problema. Incluyan detalles, como dibujos, números o palabras, para ayudar a los demás a entender sus ideas. No escriban ecuaciones” // “With your partner, create a visual display that shows your thinking about the problem. You may want to include details such drawings, numbers, or words to help others understand your thinking. Do not write equations.”
• 5 minutes: partner work time
• “Ahora vamos a hacer un recorrido por el salón para ver el trabajo de los demás. Cuando vean cada póster, escriban una ecuación que corresponda a la forma en la que el grupo representó sus ideas. Pueden escribir más de una ecuación para algunos de los problemas” // “Now we will have a gallery walk to look at each other's work. As you visit each poster write an equation that matches how the group represented their thinking. You may write more than one equation for some of the problems.”
• 10 minutes: gallery walk

• For each story problem, display the posters students created to represent it and invite students to share the equations they wrote.
• “En este problema, ¿en qué se parecen las representaciones que vemos en los pósteres y las ecuaciones que compartimos? ¿En qué se diferencian?” // “How are the representations on the posters and the equations we shared for this problem the same? How were they different?” (Some show using addition to solve and some show subtraction. They all find the same answer. Some show each object and some use numbers to represent how many objects.)