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 practice measuring lengths and writing numbers up to 120.
Students choose from any stage of previously introduced centers.
Write Numbers
Estimate and Measure
MLR8 Discussion Supports.
Synthesis: Provide students with the opportunity to rehearse what they will say with a partner before they share with the whole class.
Advances: Speaking
Required Materials
Materials to Gather
Materials from previous centers
Required Preparation
Gather materials from:
Write Numbers, Stages 1–3
Estimate and Measure, Stage 1
Launch
Groups of 2
“Now you are going to work on 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.
8 minutes: center work time
“Choose what you would like to do next.”
8 minutes: center work time
Student Facing
Choose a center.
Write Numbers
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Estimate and Measure
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Activity Synthesis
Display numbers 108, 109, 110, 111, 112.
“What do you notice about these numbers?” (They all have 100. Some have a zero and some don’t. The numbers go in order 8, 9, 10, 11, 12.)


aligns: no