Unit 7, Lesson 11
Center Day 2 (Optional)
Grade 2
Warm-up
10 mins
Number Talk: Make 100
Standards Alignment
Building On
Addressing
2.NBT.6
Add up to four two-digit numbers using strategies based on place value and properties of operations.
Building Toward
Instructional Routines
Number TalkMaterials
NoneActivity Narrative
The purpose of this Number Talk is to elicit strategies and understandings students have for adding more than 2 two-digit numbers by making 100. The unit of cents also encourages students to consider how the value could be expressed, using dollars, cents, or a combination of the two units. These understandings help students develop fluency.
Launch
- Display one expression.
- “Give me a signal when you have an answer and can explain how you got it.”
- 1 minute: quiet think time
Activity
- Record answers and strategies.
- Keep expressions and work displayed.
- Repeat with each expression.
Student Task Statement
Find the value of each expression mentally.
Activity Synthesis
- Revisit a student strategy that shows a way to make 100, and expresses the total in cents.
- Consider asking:
- “Who can restate _____’s reasoning in a different way?”
- “Who can restate _____’s reasoning, using dollars and cents?”
Activity 1
15 mins
Introduce How Close—Add to 1,000
Instructional Routines
NoneMaterials
To Copy (from Blackline Masters)
How Close? Stage 4 Recording Sheet
Number Cards 0–10
Activity Narrative
The purpose of this activity is for students to learn Stage 4 of the How Close? center. Before playing, students remove the cards that show 10 and set them aside. Each student picks 8 cards and chooses 6 of them to create 2 three-digit numbers. Each student adds the numbers and writes an equation. The score for the round is the difference between each student’s sum and 1,000. Students pick new cards so that they have 8 cards in their hands and then start the next round. The player with the lower score after 10 rounds wins.
Launch
- Give each group a set of number cards and two copies of the blackline master.
- “We are going to learn a new way to play the How Close? center.”
- “Before you play, remove the cards that show 10 and set them aside.”
- “Each person picks 8 cards and chooses 6 of them to create 2 three-digit numbers. Then add your three-digit numbers and write an equation.”
- “The score for the round is the difference between your sum and 1,000.”
- “Then pick new cards so that you have 8 cards in your hand and start the next round.”
- “The player with the lower score after 10 rounds wins.”
- Answer any questions or play a round with the class as needed.
Activity 2
25 mins
Introduce Five in a Row—Add within 1,000, with Composing
Instructional Routines
NoneMaterials
To Copy (from Blackline Masters)
Five in a Row Addition and Subtraction Stage 8 Gameboard
Activity Narrative
The purpose of this activity is for students to learn Stage 8 of the Five in a Row: Addition and Subtraction center. Students add within 1,000, with sums that require composing units when adding by place.
Then, students choose from previously introduced stages of these centers.
- Five in a Row
- How Close?
Lesson Synthesis
“When might you need to add numbers like those you worked with in these centers?”
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