Array We Go!

Learning Resource Type

Learning Activity

Subject Area

Mathematics

Grade(s)

2

Overview

In this activity, the students will look at concrete representations, followed by pictorial representations of arrays. Students will write equations, using repeated addition, to determine the total number of objects in a rectangular array.   

This activity was created as a result of the ALEX Resource Development Summit.

Phase

During/Explore/Explain
Mathematics (2019) Grade(s): 2

MA19.2.4

Using concrete and pictorial representations and repeated addition, determine the total number of objects in a rectangular array with up to 5 rows and up to 5 columns.

UP:MA19.2.4

Vocabulary

  • Rectangular array
  • Rows
  • Columns

Knowledge

Students know:
  • how to use arrays and repeated addition as multiplication strategies.

Skills

Students are able to:
  • represent the total number of objects in a rectangular array as the sum of repeated addition.
  • choose and apply addition strategies to accurately compute sums for multiple addend problems.

Understanding

Students understand that:
  • repeated addition determines the total number of items in a rectangular array.

Learning Objectives

The students will determine the number of rows and columns of concrete and pictorial rectangular arrays (up to 5 rows and 5 columns.)   

The students will determine the total number of objects in rectangular arrays.

The students will write an addition equation to express the total number of objects in rectangular arrays. 

 

Activity Details

  1. Using concrete objects (linking cubes, color tiles, food, etc.), build a rectangular array with 2 rows and 5 columns.
  2. Ask students to think about the objects and what they see. Have students talk with a shoulder partner to answer questions such as:  "How many objects do you see?", "How many rows?", "How many columns?", "How many objects are in each row or column?"
  3. Have a few students share their conversations by answering the questions discussed with his/her partner.
  4. Remind students that objects in rows and columns are called "arrays". 
  5. To make the connection from the concrete array to pictorial, build the 2 x 5 array using the Interactive Tens Frame/Work Mat resource. 
    • Use the following steps to change the number of rows and/or columns on the work mat:
      • Click on the "rows" dropdown menu.  Change to 5.
      • Click on the "columns" dropdown menu.  Change to 5.
      • Choose a color, then click the "fill" button to fill in the array.
  6. The teacher will show students how to represent the objects using a repeated addition sentence. Ex. 5 + 5 = 10, 2 + 2 + 2 + 2 + 2 = 10. 
  7. Repeat steps 1 through 6, using different combinations of rows and columns (up to 5.)
  8. Give students the equation 2 + 2 + 2 and have them represent the array in a drawing.  
  9. The teacher will show what the drawing should look like using the Interactive Tens Frame/Array Work Mat.
  10. Allow students to compare and share drawings. Repeat with other equations. 

Assessment Strategies

Quick/Formative Assessment:

Students will draw an array to match the following repeated addition equations.  The teacher will perform a quick assessment of drawings through observation to determine the next instructional steps or continue to mastery assessment. 

  1. 3 + 3 + 3 = 9
  2. 4 + 4 + 4 + 4 = 12

Students will write an equation to match the following arrays (displayed by the teacher using a drawing or Interactive Tens Frame/Work Mat.) The teacher will assess students' understanding through observation to determine the next instructional steps or continue to mastery assessment.   

  1. 5 rows and 4 columns
  2. 3 rows, 2 columns 

Students will complete the following for the assessment of mastery. 

Arrays Repeated Addition Assessment

 

Variation Tips

Some students may need to use concrete representations longer than others.  It is important not to go straight to pictures before students are ready. 

Allow students to explore/locate arrays outside the classroom, or as a homework activity. 

Background / Preparation

Become familiar with the Interactive Tens Frame/Arrays Work Mat.  You can change the grid to format a 5 x 5 work mat, suitable for the content standard. (Instructions are included in the activity section) 

Gather the concrete items needed to build arrays.

Prepare the assessment equations and arrays. Print and copy the assessment handout.  

Total Duration

16 to 30 Minutes
Interactive Ten Frame/Array Work Mat
https://mathsbot.com/manipulatives/tenFrame

Approved Date

Owner (Author)

cpteach2
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