# Lesson 16

Arrange Objects Into Arrays

### Lesson Purpose

The purpose of this lesson is for students to describe arrays and arrange objects into arrays.

### Lesson Narrative

In grade 2, students were introduced to arrays and related them to addition expressions and equations. In this lesson, students deepen their understanding of arrays as they arrange physical objects and relate arrays to multiplication and equal groups. Students use connecting cubes to represent arrays in Activity 2 and in the cool-down.

When working with array situations, students may see the equal groups in an array in either the rows or the columns. For example, when representing 3 rows of 5 chairs, they may create a 3 by 5 array or a 5 by 3 array. This is fine as long as students can correctly describe where the “3 rows of 5 chairs” are in their array. Students will learn about commutativity in the last lesson in this section, so if questions about commutativity arise, record them publicly for discussion in that lesson.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Build arrays with physical objects and describe them in terms of multiplication.
• Describe an array as an arrangement of objects into rows with an equal number of objects in each row and into columns with an equal number in each column.

### Student Facing

• Let’s make some arrays.

### Required Materials

Materials to Gather

### Required Preparation

Activity 2:

• Each group of 2 needs 60 cubes.

Building On

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

In previous grades, students saw examples of arrays, such as 10-frames, and counted objects arranged in arrays. How does that previous experience support their work with equal groups in arrays in this lesson?

### Suggested Centers

• Capture Squares (1–3), Stage 5: Multiply with 2, 5, and 10 (Addressing)
• Five in a Row: Multiplication (3–5), Stage 1: Factors 1–5 and 10 (Addressing)