standard_description: Use geometric descriptions of rigid motions to transform figures and to predict the effect of a given rigid motion on a given figure; given two figures, use the definition of congruence in terms of rigid motions to decide if they are congruent.
problem_activity: Narrative
The purpose of this activity is for students to draw arrays from a given arrangements of dots. Students draw an array from dots in equal groups to reinforce the definition of an array and then draw as many arrays as they can from 16 randomly placed dots. Having cubes or counters for students to physically rearrange would be helpful in this activity.
MLR8 Discussion Supports.
To support partner discussion, display the following sentence frames: “This array matches the diagram because . . .”, and “This array shows multiplication because . . . .”
Advances: Conversing, Representing
Required Materials
Materials to Gather
Connecting cubes or counters
Launch
Groups of 2
Give students access to connecting cubes or counters.
Activity
“Work independently to draw a way that the first group of dots in problem 1 could be arranged into an array.”
2 minutes: independent work time
“Discuss how you arranged your dots and how the array is related to multiplication with your partner.”
1 minute: partner discussion
“How did you rearrange the dots to make an array?” (Since there were 3 in each group, I put 3 dots in each row. I saw 2 groups of 6, so I made 2 rows of 6.)
Consider asking:
“Did anyone create a different array?”
“Now you are going to make as many arrays as you can from 16 dots.”
2–3 minutes: independent work time
“Share how you rearranged the dots into arrays with your partner. See if together you can come up with any other arrays.”
3–5 minutes: partner work time
Student Facing
Draw 1 way the dots could be rearranged into an array.
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Explain or show how the array is related to multiplication.
Draw ways that the dots could be arranged into arrays. Draw as many ways as you can.
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Explain or show how each array is related to multiplication.
Student Response
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Activity Synthesis
“What kinds of equal groups did you make from 16 dots? How can you see the equal groups in the arrays you made?” (I can make 2 groups of 8. I drew it as 2 rows of 8 dots.)


aligns: no