Addition | Mathematics Olympiad for Class 1 PDF Download

Let’s imagine that Rahul has 5 pencils and Timon has 7 pencils. How many pencils do they have altogether? We can find the total by using a simple math operation called Addition.

What is Addition?

Addition is when we find the total number by putting two or more numbers together. The answer we get when we add is called the sum. We use the plus sign (+) to show addition.

Examples:

• To add 4 and 6, we write: 4 + 6 (read as "4 plus 6").
• To add 2, 4, and 5, we write: 2 + 4 + 5 (read as "2 plus 4 plus 5").

How to Add one-digit and two-digit numbers?

There are different ways to add numbers. Let’s explore them:

1. Addition by Counting

Vimal has 6 chocolates in his bag. On the way to school his father bought 5 more chocolates and placed in his bag. 
Now how many chocolates are there in Vimal’s bag?

• The total number of chocolates can be calculated by counting all the chocolates one by one.
  
  

• Two-digit numbers: Here's how we can add two-digit number with one-digit number by counting one by one. 
  

2. Using a Number Line

A number line helps us add numbers by moving or jumping forward.

Steps to Add Using a Number Line:

1. Start at the First Number: Begin by finding the first number on the number line.
2. Jump Forward by the Second Number: From that first number, jump forward as many times as the second number tells you.
3. Land on the Answer: The number you land on is the answer to your addition.

Example: Add 1 + 2

Solution: Let us look into the steps given below to understand addition on a number line.

• Step 1: Consider the first number (1) as the starting point on the number line. To add 1 + 2, mark 1 on the number line.
• Step 2: Now, from the first number jump by the number of units equivalent to the second number towards the right. This is because the values on a number increase as we move towards the right-hand side. In this case, we are adding 1 + 2, therefore, we will move 2 steps to the right. This will bring us to number 3. So, 1 + 2 = 3

Here are some more examples:

(i) Peter has four trees in his plot. Kamal has 3 trees. How many trees are there in total?

We can do this using the number line as shown:
Start at 4 and jump 3 steps to the right. You will reach at 7.

So, 4 + 3 = 7.

(ii) What is 2 more than 6?

The words “more than” is used in addition.

We can find the sum using a number line as shown:

Start from 2 and jump 6 steps to the right. You will reach at 8.

So, 2 + 6 = 8.

Adding Two-digit numbers through number line

Adding two-digit numbers on a number line is similar to adding one-digit numbers, but we take bigger steps. Let’s break it down into simple steps:

Steps to Add Two-Digit Numbers:

1. Start at the Larger Number: Find the larger number on the number line.

2. Jump Forward by the Smaller Number: From the larger number, make jumps based on the smaller number.

3. Land on the Answer: The number you land on is the total or sum.

Here are some examples:

(i) What is the sum of 3 and 12?

Start from the larger number, that is, 12 here and jump 3 steps to the right. You will reach at 15. So, 12 + 3 = 15.

(ii) Koyal has 19 bangles. Praveen gifted 5 bangles to Koyal. How many bangles does Koyal have in total?

Start from the largest number, that is, 19 here, and jump 5 steps forward. You will reach at 24.
So, 19 + 5 = 24.

3. Addition of Zero

When 0 is added to any number we get the number itself

Examples:

• 0 + 1 = 1
• 2 + 0 = 2
• 0 + 11= 11
• 12 + 0= 12

4. Addition of One

When 1 is added to any number, we get the number just after it.

Examples:

• 2 + 1 = 3
• 5 + 1 = 6
• 12 + 1= 13
• 15 + 1= 16

5. Addition by Forward Counting

(i) To add 3 to 5, count 3 after 5.

So, 5 + 3 = 8.

(ii) To add 3 to 10, count 3 after 10.

So, 10 + 3 = 13.

6. Adding by regrouping or vertical addition or column addition

• For adding two numbers by regrouping or column addition, write one number below the other based on their place values, tens and ones and then add one column at a time.
• Start adding from the ones place and then move towards left to add digits in the tens place.

Examples:

• Add 4 and 7.
  So, 4 + 7 = 11.
• Add 12 and 7.
  So, 12 + 7 = 19.
• Ten tumblers are placed on a table. If Tom places 46 more tumblers on the table, how many tumblers will be there on the table?
  So, 10 + 46 = 56.