standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
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