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 any stage of previously introduced centers.
Target Numbers
Five in a Row
Get Your Numbers in Order
Required Materials
Materials to Gather
Materials from previous centers
Required Preparation
Gather materials from:
Target Numbers, Stages 1–3
Five in a Row, Stages 1–6
Get Your Numbers in Order, 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.”
30 seconds: quiet think time
Activity
Invite students to work at the center of their choice.
10 minutes: center work time
Student Facing
Choose a center.
Target Numbers
[IMG]
Five in a Row
[IMG]
Get Your Numbers in Order
[IMG]
Activity Synthesis
Display numbers 2, 1, and 6.
“Mai is playing Target Numbers. Her last sum was 78. These are the numbers she rolled on her last round. Which number should she choose as her tens and which should she choose as her ones in order to get as close to 95 as possible? Why?”


aligns: yes