The purpose of this activity is for students to solve a Take From, Change Unknown story problem using a method that makes sense to them. This is a challenging problem type for students because the amount that students are taking away or counting on is the unknown.

The activity begins with a numberless and questionless story problem to help students understand the context and structure of the story problem. Students begin the activity by looking at the problem displayed, rather than in their books. The numbers 5, 10, and 15 are used so that the focus of the activity can be on making sense of the story problem, rather than the computation. Students may benefit from acting out the story.

• Invite previously identified students to share.
• “¿Cómo muestra este método el problema-historia?” // “How does this method show the story problem?” (I can see 15 for the number they started with. 10 is how many students sat down on the rug. 5 is how many students are still standing.)

The purpose of the lesson is for students to solve a Take From, Result Unknown and a Take From, Change Unknown story problem. The story problems have the same numbers, which include a teen number, so that the focus can be on the structure of the story problems and the equations. In the Activity Synthesis, students compare the structure of the problems and in the Lesson Synthesis, students make sense of equations that represent the story problems (MP2).

• ¿En qué se parecen y en qué son diferentes los dos problemas-historia?” // “How are the two story problems the same and different?” (They have the same numbers. In one of them, we know how many to take away. In the other one, we have to figure out how many to take away.)

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any of the previously introduced stages of the listed centers.

• Shake and Spill
• Compare
• Number Puzzles

• Display 12 red counters and cover 5 yellow counters with a cup.
• “Estamos jugando con 17 fichas. Cubrí todas las fichas amarillas con el vaso. ¿Cuántas fichas están debajo del vaso? ¿Cómo lo saben?” // “We are playing with 17 counters. I covered all the yellow counters with the cup. How many yellow counters are under the cup? How do you know?”