The purpose of this activity is for students to write equations to match each story problem. Students solve the problems in any way that makes sense to them. They may write an equation in which the total or difference is before the equal sign or that uses the commutative property. Students may write equations with a box around the answer, an empty box for the unknown, or a combination of both. The number choices in this activity intentionally use sums of 10. Look for students who use counting strategies and for who use known facts to solve the problem.

The story problems in this activity are about the Mexican game, Lotería (loh-teh-REE-ah). During the Launch, students learn how the game is played and some similarities between Lotería and Bingo. Before sharing information about the game, ask students if anyone has heard of Lotería and so, what they know about how it is played. Consider showing students pictures of Lotería boards and cards.

• Invite 2–3 previously selected students to share how they represented and solved the problem.
• After each student shares, ask:
  • “¿Qué ecuación usaron para representar el problema?” // “What equation did you use to represent the problem?”
  • “¿Qué otra ecuación pueden usar para representar este problema, si hay otra?” // “What other equation could we use to represent this problem, if any?”
• Invite students to explain how the equations match the story. Highlight connections between addition and subtraction.

The purpose of this activity is for students to make sense of story problems that do not include a question. The structure of the first story makes it likely most students will infer it is an Add To, Change Unknown problem without a question being asked. The actions and transitional words make it very likely all students will ask a question similar to “How many more pictures did Clare cover?” However, the second story begins only by describing two different quantities. This could be the set-up to a Put Together/Take Apart problem or a Compare problem. This gives students an opportunity to make sense of different relationships between quantities and to revisit the different ways of asking to find the difference. When students formulate their own questions, they need to make sense of the given information in order to understand what is given and what is unknown (MP1).

• Display the equations:     
• Invite previously identified students to share their questions.
• “¿Cuál ecuación corresponde mejor al problema-historia que hizo _____?” // “Which equation best matches the story problem ______ made?”
• Consider asking, “¿Hay otra ecuación que puedan usar para representarlo o resolverlo? ¿Por qué?” // “Is there another equation you could use to represent or solve it? Why?”