Lesson 20

The purpose of this How Many Do You See is to support students in gaining fluency with sums within 10. In this activity, students have an opportunity to notice and make use of structure (MP7) because they can use the structure of the 10-frame. Students can also determine how many dots they would need to add to fill the 10-frame.

• Groups of 2
• “How many do you see? How do you see them?”  
• Flash the image.
• 30 seconds: quiet think time

• Display the image. 
• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.
• Repeat for each image.

• “Did anyone see the dots the same way but would explain it differently?”

The purpose of this activity is for students to write story problems based on equations. Students are given equations with boxes for the unknowns. They may choose any two equations. When students write story problems from equations, they reason abstractly and quantitatively (MP2). During the synthesis, students discuss which equation matches the story problem and explain how they know.

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

• “You have solved and represented different types of story problems. Today you will choose two equations and write a story problem for each equation. You may choose any two equations you want.”
• 8–10 minutes: partner work time
• Monitor for 2–3 different story problems to share during the synthesis.

• Invite previously identified students to share.
• "Which equation matches the story they wrote? How does it match the story?"

In this activity, students begin by choosing the answer to the problem they will write. They then write an equation that includes that number in any position. Finally, students write a story problem that matches their equation. This builds directly from the previous activity in which students wrote story problems, but has an added layer of complexity as students have to generate their own equations from which to write the story problem. During the launch, students generate equations in which 6 is the answer. This list should be made available to students as they generate their own equations later in the activity. This activity is the second time that students will write story problems, so students may only write story problems for which the number they chose is the result or total.

• Groups of 2
• Display \(3 + 3 = 6\) and \(10 - 6 = 4\).
• “What are some other equations we can write that have a value of 6?”
• 30 seconds: quiet think time
• Share and record responses.

• "We just wrote story problems to match given equations. Now you will write the equation and the story problem. You will choose a number. This number will be the answer to your story problem. You will write an equation with this number as the answer. Then write a story problem that matches the equation you wrote."
• 5 minutes: independent work time 
• “Share your story problem and equation with your partner. Work together to make sure your story problem and equation match.”
• 4 minutes: partner discussion
• Monitor for story problems with answers in different places to share during the lesson synthesis.

If students write story problems with an answer other than the number they circled, consider asking:

• "What equation did you write with the number you chose?"
• "How does that equation match the story you wrote?"

• “Let’s share some story problems and think of equations that could represent each one.”

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

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

• Gather materials from previous centers:
  • Capture Squares, Stages 1 and 2
  • Shake and Spill, Stages 3 and 4
  • What's Behind My Back, Stage 2

• Groups of 2
• “Now you are going to choose from centers we have already learned.”
• Display the center choices in the student book.
• “Think about what you would like to do.”
• 30 seconds: quiet think time

• Invite students to work at the center of their choice. 
• 10 minutes: center work time

• “Clare was playing What’s Behind My Back with eight connecting cubes. Her partner hid some behind her back and showed her three cubes. Clare counted, ‘7, 6, 5.’ She said her partner was hiding five behind her back. What equation can we write to show how Clare solved the problem?” (\(8 - 3 = \boxed{5}\))