# Lesson 19 Solve Problems Involving Arrays

• Let’s solve problems involving arrays.

## Warm-up Number Talk: One Less Group

Find the value of each expression mentally.

## Activity 1 Array of Colors

There are 7 rows. Each row has 5 crayons. How many crayons are there?

1. Solve this problem. Explain or show your reasoning.

2. Represent the situation with an array and an equation with a symbol for the unknown.

## Activity 2 Tyler’s Trees

For each problem:

• Write an equation with a symbol for the unknown to represent the situation.

• Solve the problem. Show your reasoning.

1. A field of coconut trees in Mexico has 5 rows of trees. Each row has 9 trees. How many trees are there?

2. After learning about growing coconuts in Mexico, Tyler wants to plant coconut trees in his backyard in Florida. His mom will only let him plant 2 rows of 4 trees in his backyard.

How many trees will Tyler plant?

## Problem 1

There are 5 rows of chairs in the room. There are 4 chairs in each row. How many chairs are in the room?

1. Write a multiplication equation to represent the situation.

2. Find the value that makes your equation true.