All Kinds of Attributes
10 min
Narrative
The purpose of this How Many Do You See? is to allow students to use subitizing or grouping strategies to describe the images they see. Students may identify lines of symmetry within the dot arrangement and use this as a strategy to determine the total number of dots. They may also consider smaller arrays, or chunk the image into small groups and multiply or add.
In this activity, students have an opportunity to look for and make use of structure (MP7) because the arrangement contains smaller arrays and line symmetry.
Launch
- Groups of 2
- “How many do you see? How do you see them?”
- Display the image.
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Record responses.
Student Task
How many do you see? How do you see them?
Sample Response
20 dots. Sample reasoning:
- A vertical stack of 6 in the middle, 2 vertical groups of 4 on either side of it, and 2 triangular groups of 3 on either end: 6+(2×4)+(2×3)=20
- A 6-dot line of symmetry separating 2 sets of 7 dots: 7+6+7=20
- 3 groups of 7 is 21, so 2 groups of 7 and a group of 6 is 20.
- A 3-by-4 array in the middle, plus 2 groups of 3 on the left and right sides, plus 2 dots at the top and bottom: (3×4)+(2×3)+2=12+6+2=20
Activity Synthesis (Teacher Notes)
- “How does the arrangement of dots help you find the number?” (It has lines of symmetry. We can count the dots on one side of the line and double it, without counting one by one.)
- Consider asking:
- “Who can restate the way _____ saw the dots in different words?”
- “Did anyone see the dots the same way but would explain it differently?”
- “Does anyone want to add an observation to the way _____ saw the dots?”
Standards
- 4.G.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
- 4.G.A.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
20 min
10 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
All Kinds of Attributes
10 min
Narrative
The purpose of this How Many Do You See? is to allow students to use subitizing or grouping strategies to describe the images they see. Students may identify lines of symmetry within the dot arrangement and use this as a strategy to determine the total number of dots. They may also consider smaller arrays, or chunk the image into small groups and multiply or add.
In this activity, students have an opportunity to look for and make use of structure (MP7) because the arrangement contains smaller arrays and line symmetry.
Launch
- Groups of 2
- “How many do you see? How do you see them?”
- Display the image.
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Record responses.
Student Task
How many do you see? How do you see them?
Sample Response
20 dots. Sample reasoning:
- A vertical stack of 6 in the middle, 2 vertical groups of 4 on either side of it, and 2 triangular groups of 3 on either end: 6+(2×4)+(2×3)=20
- A 6-dot line of symmetry separating 2 sets of 7 dots: 7+6+7=20
- 3 groups of 7 is 21, so 2 groups of 7 and a group of 6 is 20.
- A 3-by-4 array in the middle, plus 2 groups of 3 on the left and right sides, plus 2 dots at the top and bottom: (3×4)+(2×3)+2=12+6+2=20
Activity Synthesis (Teacher Notes)
- “How does the arrangement of dots help you find the number?” (It has lines of symmetry. We can count the dots on one side of the line and double it, without counting one by one.)
- Consider asking:
- “Who can restate the way _____ saw the dots in different words?”
- “Did anyone see the dots the same way but would explain it differently?”
- “Does anyone want to add an observation to the way _____ saw the dots?”
Standards
- 4.G.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
- 4.G.A.1·Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.