Lesson 3: Arrays and Equal Groups

Getting Started

Questions to Explore

What are some strategies we can use to multiply and divide?

Facts and Definitions

The four strategies for multiplication are arrays, equal groups, repeated addition, and number lines.

Skills

Interpret products of whole numbers (for example, interpret 5×7 as the total number of objects in 5 groups of 7 objects each)
Interpret and create arrays that model multiplication
Use equal groups to model multiplication

Materials

Cheerios, Goldfish, or another small snack food
counters (kit)
fine point dry-erase markers (kit)
Interactive Notebook
laminated multiplication strategies mat (kit)
small paper plates (kit)
whiteboard (kit)

Introduction

Materials: counters (kit), fine point dry-erase markers (kit), Interactive Notebook, whiteboard (kit)

Write 5×4=20 on the whiteboard, and pose the following questions:

What are the factors? (5 and 4)
What is the product? (20)
What can you draw to show this multiplication problem?

Give your child the whiteboard and a dry-erase marker so that he can draw a way to show the problem. He might draw an array or 5 circles or boxes that have 4 dots or other small objects each inside of them. If he'd prefer, allow him to show the problem using counters. (5 groups of 4 counters)

Now, say, "You've already learned many strategies for adding numbers. What are some of them?" His answer may include doubles, fact families, turn-around facts/commutative property of addition, making 10, adding multiples of 10, carrying, and regrouping. If needed, remind him of some of these strategies, and review the "Math Strategies Review" sheets in his Interactive Notebook. Say, "Just like with addition, there are some important strategies related to multiplication."