standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Narrative
The purpose of this activity is for students to experience center choice time for the first time. Students choose from activities that offer practice counting up to 20 objects or adding within 10. Students choose from previously introduced centers and are encouraged to choose the center that will be most helpful for them at this time.
Counting Collections
Number Race
Check it Off
Five in a Row: Addition and Subtraction
Students will choose from these centers throughout the section. Keep materials from these centers organized to use each day.
Engagement: Provide Access by Recruiting Interest.
Use visible timers or audible alerts to help students anticipate and prepare to transition between center activities.
Supports accessibility for: Social-Emotional Functioning, Organization
Required Materials
Materials to Gather
10-frames
Materials from previous centers
Two-color counters
Required Preparation
Gather materials from previous centers:
Counting Collections, Stage 1
Number Race, Stage 3
Check it Off, Stage 1
Five in a Row: Addition and Subtraction, Stage 1
Launch
Groups of 2
“Now you are going to 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.
8 minutes: center work time
“Choose what you would like to do next.”
8 minutes: center work time
Student Facing
Choose a center.
Counting Collections
[IMG]
Number Race
[IMG]
Check it Off
[IMG]
Five in a Row: Addition and Subtraction
[IMG]
Activity Synthesis
“How did you and your partner work well together during centers today?”


aligns: no