Lesson 3

The purpose of this Number Talk is to elicit strategies and understandings students have for adding within 100. These understandings help students develop fluency and will be helpful later in this lesson when students will need to be able to add up the total number of students represented in a picture graph. When students use strategies based on place value to add they look for and make use of structure (MP7).

• Display one expression.
• “Give me a signal when you have an answer and can explain how you got it.”
• 1 minute: quiet think time

• Record answers and strategy.
• Keep expressions and work displayed.
• Repeat with each expression.

• “How was place value helpful as you added these numbers?” (I was able to use tens and ones to help me find the sum.)
• Consider asking:
  • “Who can restate _____’s reasoning in a different way?”
  • “Did anyone have the same strategy but would explain it differently?”
  • “Did anyone approach the problem in a different way?”
  • “Does anyone want to add on to _____’s strategy?”

The purpose of this activity is for students to read a scaled picture graph. A scale of 5 is used to encourage skip-counting because students skip-counted by 5 in grade 2. The questions in the task focus on the structure of a scaled picture graph and strategies for reading them.

• Groups of 2
• “What is your favorite sport or activity outside of school?”
• Share responses.
• Display the first image of the single-unit scale picture graph.
• “What do you notice? What do you wonder?” (Students may notice: The graph is about students’ favorite sports. There are a lot of smiley faces. Each smiley face represents 1 student. It takes a lot of time to count up the students in each category. Students may wonder: How many student responses are shown in the whole graph? How could we make the graph take up less space?)
• 1 minute: quiet think time
• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Share and record responses.

• “Work with your partner to find how many students are represented in the graph.”
• 3–5 minutes: partner work time
• Monitor for students who group the smiley faces by 2, 5, or 10 to make them easier to count.
• Have students who grouped the smiley faces share their strategies for how they found the total number of students represented in the graph.
• If no students use this strategy ask, “How could grouping the pictures in the graph make them easier to count?” (We could circle tens so we could count by ten. It would be easier to keep track of your count than by counting by ones.)
• Display the second image of the scaled picture graph.
• “How could we count the total number of students in this graph?”
• 2 minutes: partner work time
• Math Community: As students work, monitor for examples of the “Doing Math” actions.

• “How did you find the total number of students represented in the graph?”
• “How could you use counting by 5 to find the total number of students represented in the graph?”

• “In a graph where there’s a lot of data we can adjust the scale so each picture represents more than 1 object. When each picture represents something other than 1, we say that it’s a scaled picture graph. The key tells us that in this graph, each smiley face represents 5 students.”

The purpose of this activity is for students to interpret a scaled picture graph and write questions that can be asked based on the data represented in a scaled picture graph.

• Groups of 2
• Display the graphs for all to see.
• “What are some strategies you could use to read the graphs?” (In the Flowers I Saw on the Way Home graph I could count each category by 5 since each picture represents 5 flowers.)
• 1 minute: quiet think time
• Share and record responses.

• “Now, we’re going to answer some questions about the scaled picture graphs. You will also have a chance to write your own question that can be asked based on each graph.”
• 8–10 minutes: partner work time
• If there is time, have groups trade books and answer each other’s questions.
• Math Community: As students work, monitor for examples of the “Doing Math” actions.

• “How did you answer the questions about the graph?”
• “What does the key tell us about each picture in the graph?”

• Have students share responses to the questions they answered and explain their reasoning.
• Consider asking:
  • “How did you use the scale to answer the questions?” (I counted by the number that each picture represented, like by 5 for the flowers and by 2 for the students.)
• Share a variety of student written questions.
• Consider asking:
  • “How did you know your question could be answered with the graph?” (The data you needed to answer the question was in the graph.)
  • If time ask, “What questions cannot be answered by this graph?” (How many students' favorite type of book is graphic novels?)