standard_description: Represent addition, subtraction, multiplication, and conjugation of complex numbers geometrically on the complex plane; use properties of this representation for computation. For example, (-1 + Ö3i)^(3) = 8 because (-1 + Ö3i) has modulus 2 and argument 120°.
problem_activity: Narrative
The purpose of this warm-up is for students to subitize or use grouping strategies to describe the number of dots they see and how they see them. Students have an opportunity to notice and make use of structure (MP7) because each dot image builds from the previous one, and students can think about adding on one or rearranging the dots rather than counting.
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.
Repeat for each image.
Student Facing
How many do you see?
How do you see them?
[IMG]
[IMG]
[IMG]
Student Response
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Activity Synthesis
“What helped you see how many dots there were each time?” (In the second image I saw 3 and 1 more and I know that is 4. In the last one I saw 2 and 2.)


aligns: no