The purpose of this activity is to write story problems for equations with an unknown value. In each given pair of addition or subtraction equations, one equation has the starting value unknown. Students may write Add To, Take From, Put Together/Take Apart, or Compare problems. When students contextualize the equations and make connections between the stories their peers share and the equations, they reason abstractly and quantitatively (MP2).

• Display this text: “Hay 23 pelotas de béisbol en el gimnasio y 37 pelotas de béisbol en el patio de recreo” // “There are 23 baseballs in the gym and 37 baseballs on the playground.”
• “Esta es la historia de Andre. ¿La ecuación  representa la historia de Andre?” // “This is Andre’s story. Does the equation represent Andre’s story?” (No, Andre’s story doesn’t have a question or anything happening. It might match, but it needs more information or a question.)
• “¿Cómo mejorarían la historia de Andre?” // “How would you improve Andre’s story?” (He could add a question like, “How many more baseballs are on the playground than in the gym?” He could keep it about baseballs, but add some things that happen. He might say someone took the 23 baseballs to the playground and now there are 37 baseballs on the playground and ask how many were already on the playground.)
• Record student suggestions for revising Andre’s story.
• “¿La ecuación  representa alguna de estas historias?” // “Does the equation represent any of these stories now?” (It represents the question about how many more baseballs are on the playground.)

The purpose of this activity is for students to write math stories. Several options are available for fueling their imagination. Examples:

• Look at pre-selected images, such as the one used in the Estimation Exploration in this lesson or those in the optional blackline master.
• Look at images in magazines or newspapers.
• Look around the classroom.
• Go for a walk around the school or community.

Whichever source is used for ideas, students write a story problem that connects to mathematical ideas they have found. If students come up with a context, but are not able to count or estimate the quantities they see, display a set of numbers (such as 11, 25, 38, 56, 77, 93) that students can use to write their story problem.

When students write math stories based on images or things in their environment, and eventually answer those questions, they model with mathematics (MP4).

• Invite selected students to share their stories.