Lesson 19

The purpose of this Choral Count is to invite students to practice counting by 10 and notice patterns in the count. These understandings help students develop fluency with the count sequence and will be helpful as students begin working with numbers beyond 10.

• "Count by 10, starting at 0."
• Record as students count.
• Stop counting and recording at 100.
• "Count backward by 10, starting at 100."
• Record as students count.
• Stop counting and recording at 0.

• "What patterns do you see?"
• 1–2 minutes: quiet think time
• Record responses.

• "How did you know what number would come next as you counted backward?"

The purpose of this activity is for students to write two 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 is before the equal sign, or that uses the add in any order property. Students may write equations with a box around the answer, an empty box for the unknown, or a combination of both.

The story problems in this activity are about the Mexican game, Lotería. 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 this game, and what they know about how it is played. Consider showing students pictures of Lotería boards and cards.

• Groups of 2
• Give students access to connecting cubes or two-color counters.
• “We have been solving problems about different games people play. Today we will solve problems about a game called Lotería. Has anyone played Lotería?"
• Share responses.
• If needed, "Lotería is a very popular game played in Mexico. It is similar to the game bingo. Instead of numbers, the caller picks a card with a picture on it. If the picture is on your board, you cover it. Many people use beans or small rocks to cover the pictures. When you have four pictures covered in a row you call out, ‘Lotería!’”
• Consider displaying images of the game boards and picture cards used in the game.

• “Let’s solve some problems about students playing Lotería.”
• Read the task statement.
• 6 minutes: independent work time
• “Share your equations with your partner. Explain how they match the stories.”
• 3 minutes: partner discussion

• Invite students to share the equations they wrote for each story problem and explain how they match the story.

The purpose of this activity is for students to make sense of story problems that do not include a question. In some story types, like Add To, Change Unknown, students can infer what the question in the story is without it being asked. In problem types like Compare, there are multiple questions that can be answered, all of which have different equations, solutions, and methods of solving. In presenting students with problems without questions, they strengthen their understanding of connections between story problems and the equations that match. 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).

• Groups of 2
• Give students access to connecting cubes or two-color counters.

• "Now you will read story problems that don't have a question. Your job is to write a question for each problem. Then solve the problem."
• 5 minutes: independent work time
• “Share your question and equation with your partner.”
• 3 minutes: partner discussion
• Monitor for students who wrote different questions for the problem with Diego and Noah.

• Invite previously identified students to share.
• Display the equations:
  • \(2 + 9 = \boxed{\phantom{11}}\)
  • \(9 - 2 = \boxed{\phantom{7}}\)
  • \(2 + \boxed{\phantom{7}} = 9\)
• “Which question does each of these equations represent? How do you know?”