Arrange Objects into Arrays

10 min

Narrative

The purpose of this Warm-up is to elicit ideas students have about objects arranged in an array, which will be useful when students arrange equal groups into arrays in a later activity. While students may notice and wonder many things about this image, ideas around arrangement and equal groups are the important discussion points. When students notice the arrangement of the eggs, they look for and make use of structure (MP7).

Launch

  • Groups of 2
  • Display the image.
  • “What do you notice? What do you wonder?”
Teacher Instructions
  • “Discuss your thinking with your partner.”
  • 1 minute: partner discussion
  • Share and record responses. 

Student Task

What do you notice? What do you wonder?

Open carton of 12 eggs.

Solution Steps (4)
  1. 1
    Observe the arrangement of eggs in the carton
    →12 eggs arranged in 2 rows and 6 columns
  2. 2
    Identify rows (horizontal groups)
    →2 rows with 6 eggs in each row → 2 groups of 6
  3. 3
    Identify columns (vertical groups)
    →6 columns with 2 eggs in each column → 6 groups of 2
  4. 4
    Recognize the array structure
    →The eggs form an array: same number in each row, same number in each column

Sample Response

Students may notice:
  • There are 12 eggs.
  • There are 2 groups of 6.
  • I see 6 groups of 2.
Students may wonder:
  • How many eggs would be in two cartons?
  • Are there other equal groups that I don’t see?
Activity Synthesis (Teacher Notes)
  • “How does having the eggs in a carton help you see equal groups?” (I can see how they could be split into equal groups. I can see 6 eggs in each row. I can see 6 groups of 2.)
  • “The eggs are arranged in an array. An array is an arrangement of objects in rows and columns. Each column must contain the same number of objects as the other columns, and each row must have the same number of objects as the other rows.”
Standards
Building On
  • 2.OA.4·Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.
  • 2.OA.C.4·Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.
Building Toward
  • 3.OA.1·Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each. <em>For example, describe a context in which a total number of objects can be expressed as 5 × 7.</em>
  • 3.OA.A.1·Interpret products of whole numbers, e.g., interpret <span class="math">\(5 \times 7\)</span> as the total number of objects in 5 groups of 7 objects each. <span>For example, describe a context in which a total number of objects can be expressed as <span class="math">\(5 \times 7\)</span>.</span>

15 min

20 min