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 choose from activities that offer practice working with two-digit numbers. Students choose from previously introduced centers.
Mystery Number
Get Your Numbers in Order
Greatest of Them All
Required Materials
Materials to Gather
Materials from previous centers
Required Preparation
Gather materials from previous centers:
Mystery Number, Stage 1
Get Your Numbers in Order, Stage 1
Greatest of Them All, Stage 1
Launch
Groups of 2
“We are going to choose from centers we have already learned.”
Display the student page.
“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.
10 minutes: center work time
“Choose what you would like to do next.”
10 minutes: center work time
Student Facing
Choose a center.
Mystery Number
[IMG]
Get Your Numbers in Order
[IMG]
Greatest of Them All
[IMG]
Activity Synthesis
“How were the two centers you worked on the same? How were they different?”


aligns: no