## Key Concepts

- Identify if a group is an array

## Introduction

To find the totals by using an array, first, we have to know about the repeated addition. Let’s know what repeated addition is and how we can add numbers repeatedly.

### Repeated addition

We can model repeated addition with an array. Let’s add the same number again and again and find the answer.

**Adding the same number (addend) over and over.**

**3 + 3 + 3 + 3 = 12**

Here we are adding 3 stars repeatedly four times.

**Example:**

Model repeated addition with an array.

Here we can add 4 smileys repeatedly.

4 + 4 + 4 + 4 = 16

**Arrays:**

Arrays have equal rows and equal columns.

Here the image contains 5 equal rows and 3 equal columns.

Arrays have** equal rows.**

There are 5 equal rows. Each row has 3 dots.

Arrays have **equal columns**.

There are 3 equal columns. Each column has 5 dots.

We can define an array as a set that shows equal groups in rows and columns.

Here we can see that there are three rows and four columns.

**Example 1:**

Count the number of rows and columns present in the given image.

Count the number of rows.

Then we have to count the number of columns.

From the figure, we can say that there are 4 rows and 4 columns in the image.

**Example 2:**

Write the number of rows and columns the given image has.

**Solution:**

There are 3 columns and two rows. Each column has two stars, and each row has 3 stars.

**Example 3:**

Write two equations which explain the array.

**Solution:**

There are 4 objects in each row if we count row-wise.

There are 2 objects in each column if we count column -wise.

By rows the required equation is 4 + 4 = 8

By columns the required equation is 2 + 2 + 2 + 2 = 8.

**Example:**

Which addition statement describe the array?

**Solution:**

There are 2 rows and 5 columns.

So, the equation for the array is,

5 + 5

2 + 2 + 2 + 2 + 2

So, the required answer is 5 + 5.

## Exercise

- Write two equations that explain the array.

- Write the equation by rows for the array.

- Write two equations that explain the array.

- Write the equation by rows for the array.

- Write the equation by columns for the array.

- Write the equation by rows for the array.

- Write two equations that explain the array.

- Write the equation by columns for the array.

- Write two equations that explain the array.

- Write the equation by columns for the array.

### Concept Map

### What we have learned

- How to identify a group of an array?