standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Narrative
The purpose of this activity is to build towers with solid shapes and count how many solid shapes are in the tower. Students will need to think strategically about which shapes to use and their properties. For stacking shapes, it is important to have flat faces. Students may notice that spheres can not be used to build towers. Pyramids and cones can be used as the top of the tower, but nothing can be stacked on top of them. The purpose of the activity synthesis is to discuss the attributes of shapes and why students chose the shapes they did to build their towers.
MLR8 Discussion Supports.
During group work, invite students to take turns sharing their responses. Ask students to restate what they heard using precise mathematical language and their own words. Original speakers can agree or clarify for their partner.
Advances: Listening, Speaking
Required Materials
Materials to Gather
Geoblocks
Solid shapes
Launch
Groups of 2
Give students access to solid shapes and geoblocks.
“Use solid shapes to make the tallest tower you can.”
3 minutes: independent work time
Activity
“Compare with your partner. How are your towers the same? How are they different?” (Sample response: We both used a lot of cubes. My tower has a point on top. My partner’s tower is taller.)
30 seconds: quiet think time
1 minute: partner discussion
Share responses.
“Write a number to show how many solid shapes you used in your tower.”
2 minutes: independent work time
“Did you or your partner use more solid shapes in their tower?”
30 seconds: quiet think time
1 minute: partner discussion
Share responses.
Student Facing
How many solid shapes did you use in your tower?
_______________
Activity Synthesis
Invite students to share their towers.
“What shapes did ____ use?” (There are some cubes and a pyramid on top.)
“How many shapes did ___ use?” (4)
“Did you use a sphere in your tower? Why?” (No. I could not put anything on top of it because it’s round. It rolled away because it’s round.)
“Did you use a cone in your tower?” (It worked at the very top but I could not put anything on top of the cone.)


aligns: no