standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Narrative
The purpose of this activity is for students to create their own relevant mathematical questions and use their understanding of addition and subtraction to answer questions about their own and their peers' survey data.
Launch
Combine pairs into groups of 4
Activity
“Switch graphs. Use the sentence stems or create your own questions about the other group’s graphs.”
1
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2 minutes: independent work time
4 minutes: partner work time.
“Take turns to ask each other the questions you came up with and use your own graph to answer.”
“When possible, write down an equation to show your reasoning.”
5 minutes: group discussion.
Monitor for students who write equations to show the categories they combine or compare when answering their peers' questions.
Student Facing
Trade graphs. Create questions about the other group’s graph.
Sentence stems:
How many students picked ___________ and __________ all together?
How many more students picked _______ than _______?
Take turns asking and answering questions.
Student Response
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Advancing Student Thinking
If students rely on counting to find solutions rather than adding or subtracting, consider asking "What equation could you write to represent the categories in the question?"
Activity Synthesis
Invite previously selected students to share.
“Where do we see the equations in their graph? What does the equation mean?”
“What’s the difference between answering the questions from a bar graph and answering them from a picture graph?”


aligns: no