Table of contents 
Addition 
Addition up to 20 
Subtraction 
Subtracting within 20 
Addition and Subtraction Relationship 
1 Crore+ students have signed up on EduRev. Have you? 
EduRev Tips: It is easy to add if we start from the bigger number while doing addition by counting forward.
Let us look at the following situations to know the properties of addition.
1. Adding two numbers by changing their order
While adding two numbers, the sum does not change, even if we change the order of the numbers.
2. Adding 0 to a number
There are 4 friends playing. No more friends joined them.
When we add 0 to a number, the sum is the number itself.
EduRev Tips: To add 1digit number to 10, just replace the 0 with the number. It becomes the ones place of the ‘sum’.
EduRev Tips: Adding by making a group of 10 changes the question to “adding to 10”.
Step 1: Add any two numbers first. Get the answer.
Step 2: Now, count on to add the third number in the answer you got in step 1.
Thus, Ms Yashvi got the answer 9 cookies because 3 + 2 + 4 = 9.
EduRev Tips: While adding three numbers, it makes no difference which two numbers are added first.
EduRev Tips: When we write the smaller number below the bigger number for subtraction,
it is called vertical subtraction.
EduRev Tips: We count backward by ones to subtract. The number we stop at is the difference.
Let us look at the following situations to know the properties of subtraction.
1. Subtracting 0 from a number
A monkey has 6 bananas. The monkey ate none. Now, 6 bananas are left with him.
When 0 is subtracted from a number, the difference is the same number.
2. Subtracting 1 from a number
A monkey has 5 bananas. The monkey ate 1 banana. Now, 4 bananas are left with him.
When 1 is subtracted from a number, the difference is the number that is just before it.
3. Subtracting a number from itself
A monkey has 4 bananas. The monkey ate all of them. No bananas are left with him now.
When a number is subtracted from itself the difference is 0.
Case 1: When the ones digit is same in both the numbers.
Case 2: When the ones digit in a 2digit number is greater than the 1digit number.
Parag: How many pencils are left with you now?
Sheetal: 14
Parag: How?
Sheetal: I subtracted the pencils given to you from the total number of pencils I had as follows.
So, 19  5 = 14.
You can also count backward to subtract. Start from 19 and count back 5 ones as 19, 18, 17, 16, 15, 14.
Sheetal: This is how I am left with 14 pencils.
Manisha: Add 10 and 5 in any order, the answer will remain the same.
10 + 5 = 15 or 5 + 10 = 15
Dhruv: I can write two subtraction statements for 10 + 5 = 15
or 5 + 10 = 15 as follows:
15  5 = 10 and 15  10 = 5.
Aryan: To each addition fact there are two subtraction facts.
10 videos36 docs23 tests

Use Code STAYHOME200 and get INR 200 additional OFF

Use Coupon Code 
10 videos36 docs23 tests
