The purpose of this activity is for students to make sense of a problem before solving it by familiarizing themselves with a context and the mathematics that might be involved (MP1). Students are asked to tell a story about an image in order to generate observations that lead them to ask mathematical questions about the context. This prepares students to solve story problems about the given context in the second activity.

• Invite several students to share one question with the class. 
• Record responses.
• If needed, ask, “Can this question be answered by the image? How do you know?”
• “What do these questions have in common? How are they different?” (Some of them use the same numbers. Some ask to find the total and others ask to find the difference.)

The purpose of this activity is for students to solve a variety of story problems that could be represented as an equation with an unknown addend. Students solve Put Together/Take Apart, Addend Unknown; Compare, Difference Unknown; and Add To, Change Unknown problems. Students may solve in any way they want and should be encouraged to explain how their representations and solution methods match the actions or quantities in each story (MP2). Listen for the ways students explain how their representations, including any expressions or equations they may use, represent the story.

Look for ways students' understanding of story problems and the types of representations they use have developed over the course of the unit. In particular, look for students who show they may be thinking flexibly about addition or subtraction when solving problems that involve an unknown addend, including Add To, Change Unknown problems. This idea is explored in the Lesson Synthesis, although all students are not expected to use this strategy at this point in the course.

• Invite previously selected students to share for the first problem.
• Record student methods and annotate their thinking with equations, as needed.
• “How are these strategies the same? How are they different?” (They both show thinking about the total and one of the parts. They both show a way to find the other part. One strategy shows thinking about counting on. It’s like finding an unknown addend. The other shows taking away. It’s like thinking about subtraction.)
• Repeat with the second problem.
• “How are these story problems the same? How are they different?” (You can solve both of them by thinking about how much you need to count on or add. One is about a total and parts, the other is about comparing.)

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

• Capture Squares
• Shake and Spill
• What’s Behind My Back?

• “What is one thing you learned or got better at by working on the activities you chose?”