Operations on Numbers

Mixed Operations

We have learned about the mathematical operations – Addition and Subtraction.

• Addition: To find out the total
• Subtraction: To find out the difference

Addition and Subtraction Facts:

1. When we add 0 to a number or subtract 0 from a number, we get the same number.

Example :

3+0=3

3-0=3

2. When we add 1 to a number, we get the number that comes after. When we subtract 1 from a number, we get a number that comes before that number.

Example :

4+1=5

4-1=3


3. Addition fact:


Adding 2 + 3 and 3 + 2 get the same answer as 5.

4. Subtraction fact :


Subtracting 2 from 5, we will get the answer 3, and subtracting 3 from 5 we will get the answer 2.

5. Fact family :


To find missing numbers in addition or subtraction, we can use fact families.

Word Problems

We can solve a word problem involving addition or subtraction by following steps.

Step 1 : Find out which operation we need to do.

Step 2 : Identify the numbers with which we have to do the operation.

Step 3 : Find out the answer.

Example :

Question 1: Joy has 2 books. Merry gives him 2 more books. How many books does Joy has now?

Solution:

Step 1: Here we need to find the total number of books. So, we need to do the addition.

Step 2: Joy has 2 books and he got 2 more books. So, we need to add 2 and 2.

Step 3:

2+2=4

Joy has 4 books in total.

Question 2 : Tom has 7 toy cars. Max has 3 toy cars. How many more cars does Tom has than Max?

Solution:

Step 1: Here we need to find the difference. So, we need to do the Subtraction.

Step 2: The number 7 is the larger number here. So, we need to subtract 3 from 7.

Step 3: 7-3=4

Tom has 4 more cars than the Max.