standard_description: Determine the unknown whole number in an addition or subtraction equation relating to three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 + ? = 11, 5 = �� – 3, 6 + 6 = ��.
problem_activity: Narrative
The purpose of this What Do You Know About _____? is to invite students to share what they know and how they can represent the number 20.
Launch
Display the number 20.
“What do you know about 20?”
1 minute: quiet think time
Activity
Record responses.
Student Facing
What do you know about 20?
Student Response
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Activity Synthesis
“What connections do you see between different answers?”
Pick two addition expressions that use different addends and ask, “How are these two expressions related?”


aligns: no