standard_description: Solve real world and mathematical problems involving perimeters of polygons, including finding the perimeter given the side lengths, finding an unknown side length, and exhibiting rectangles with the same perimeter and different areas or with the same area and different perimeters.
problem_activity: Narrative
The purpose of this How Many Do You See is for students to use grouping strategies to describe the images they see.
When students use grouping to find the total in a multiple of tens, they look for and make use of structure (MP7).
Launch
Groups of 2
“How many do you see? How do you see them?”
Flash the image.
30 seconds: quiet think time
Activity
Display the image.
“Discuss your thinking with your partner.”
1 minute: partner discussion
Record responses.
Student Facing
How many do you see? How do you see them?
[IMG]
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Activity Synthesis
“What expressions could we record for the different ways that students saw the tens?” (
\(6 \times 10\)
, because some students saw 6 groups of 10.
\(3 \times (10 \times 2)\)
, because some students saw 2 rows of 10, then multiplied by 3.
\((3 \times 10) \times 2\)
, because some students multiplied 3 times 10 for each column, then multiplied by 2.)
Consider asking:
“Who can restate in different words the way _____ saw the tens?”
“Did anyone see the tens the same way but would explain it differently?”
“Does anyone want to add an observation to the way _____ saw the tens?”


aligns: no