Explanation

About the Math, Learning Targets, and Rigor

This standard calls for students to use rectangular arrays to work with repeated addition. This is a building block for multiplication in 3rd Grade. Students should explore this concept with concrete objects (e.g., counters, bears, square tiles, etc.) as well as pictorial representations on grid paper or other drawings.

Based on the commutative property of addition, students can add either the rows or the columns and still arrive at the same solution.

A rectangular array is an arrangement of objects in horizontal rows and vertical columns. Arrays can be made out of any number of objects that can be put into rows and columns.

• All rows contain the same number of items and all columns contain an equal number of items.
• Have students use objects to build all the arrays possible with no more than 25 objects. Their arrays should have up to 5 rows and up to 5 columns.
• Ask students to draw the arrays on grid paper and write two different equations under the arrays: one showing the total as a sum by rows and the other showing the total as a sum by columns.
• Both equations will show the total as a sum of equal addends.

Resources

Videos

• Instructional Video (12:17 - 14:40)
• Khan Academy
  • scroll to find 2.OA.4, click on a skill, watch videos on left side in each skill
• Learn Zillion

EngageNY Lessons

Extra Practice

• North Carolina Tasks
• Illustrative Math Tasks
• Howard County Tasks
  • Click on 2nd grade at bottom, then 2.OA.4
• Common Core Sheets

Released Assessment Questions

2.OA.4 Student Example

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