standard_description: Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), 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.
problem_activity: Narrative
The purpose of this activity is for students to have another chance to practice skip-counting by 2, 5, and 10 and addition and subtraction within 1,000.
Required Materials
Materials to Gather
Materials from previous centers
Required Preparation
Gather materials from:
Write Numbers, Stage 4
Target Numbers, Stages 6 and 7
Five in a Row, Stages 7 and 8
How Close, Stage 4
Launch
“Now you will choose from centers we have already learned.”
Display the center choices in the student book.
“Think about what you would like to do first.”
30 seconds: quiet think time
Activity
Invite students to work at the center of their choice.
15
–
20 minutes: center work time
“Choose what you would like to do next.”
15
–
20 minutes: center work time
If time allows, have students choose a third center to work on.
Student Facing
Choose a center.
Write Numbers
[IMG]
Target Numbers
[IMG]
Five in a Row
[IMG]
How Close
[IMG]
Activity Synthesis
Invite 2-3 students to share their favorite method for adding and subtracting within 1,000.


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