Download class – 3 subject – mathematics

CLASS – 3
SUBJECT – MATHEMATICS
CHAPTER - 2
ADDITION
• Addition means putting four or more numbers together.
• The numbers we add are called addends.
• The number which we get after adding is called the sum of numbers.
456 {ADDEND}
+ 212 {ADDEND}
=
668 {SUM}
ADDITION OF FOUR DIGIT NUMBERS WITHOUT CARRY OVER
First add the ones, then the tens, then add the
Hundred, at last add the thousands.
For eg.- Add the following
1. Th H T O
4 2 0 5
+ 3 1 5 2
7 3 57
2. Th H T O
5 3 4 6
+ 2 4 2 1
7 7 6 7
ADDITION OF FOUR DIGIT NUMBERS WITH CARRY OVER
If the sum of digits in the ones, tens or hundreds column is more than 9, we regroup the numbers and
carry - over to the next column.
For eg.-
Th H T O
1 1 1
6 4 5 6
+ 2 8 6 8
9 3 2 4
PROPERTIES OF ADDITION
• Numbers can be added in any order, but the answer remains the same.
For eg.- 4 + 5 = 9
5 + 4 = 9
• When zero is added to a number, the answer is the number itself.
For e.g. -8 + 0 = 8
WORDPROBLEMS
Q.1. A vegetable seller earned Rs 485 on Monday and Rs 649 on Tuesday. How much did he earn on
these two days?
Sol.1. Earning on Monday
= 485
Earning on Tuesday
= 649
Earning on the both days = 485 + 649 = 1134
Ans-The vegetable seller earned Rs 1134.
Q.2. In a garden, there are 375 roses, 642 marigolds and 142 lilies. How many flowers are there in the
garden?
Sol.2.
Roses in the garden
= 375
Marigolds in the garden
= 642
Lilies in the garden
= 142
Total flowers in the garden
= 375+642+142 =1159
Ans -There are 1159 flowers in the garden.
CHAPTER-3 SUBTRACTION
Subtraction facts
* Subtraction -Subtraction is taking away one number from another number.
* Difference - The result of a subtraction problem.
* Regrouping - To change Hundreds into Tens and Tens into Ones.
Subtraction without borrowing:
Example - Subtract 2035 from 9387
Step 1- Subtract the ones
Th H T O
9 3 8 7
-2 0 3 5
2
Step 2 - Subtract the tens
Th H T O
9 3 8 7
- 2 0 3 5
5
2
Step 3 - Subtract the hundreds
Th H T O
9 3 8 7
- 2 0 3 5
3 5 2
Step 4 - Subtract the thousands
Th H T O
9 3 8 7
-2 0 3 5
___________
7 3 5 2
Thus 9387 - 2035 = 7352
Subtraction with borrowing - Ex. Subtract 5864 from 7652
Th H T O
6 15 14 12
7 6 5 2
-5 8 6 4
____________
1 7 8 8
Ans. 1788
Properties of subtraction 1. When a number is subtracted from itself, the difference is 0.
e.g. 15 - 15 = 0
2. When 0 is subtracted from a number, the difference is the number itself.
e.g. 20 - 0 = 20
Checking of subtraction sums:
To check any subtraction sum, add the difference to the smaller number. You
Should get the bigger number as the answer.
Example: Subtract 5724 from 7656 and check:
Checking
Th H T O
Th H T O
6 16
1 9 3 2
7 6 5 6
-5
7 2 4
___________
1 9 3 2
Addition and Subtraction together -
+5 7 2 4
____________
7 6 5 6
If addition and subtraction are given together, we always add first and
Then subtract:
Example: Solve 3210 + 1540 – 1580
Solution – By using BODMAS rule
Step 1 (Addition)
Th H T O
3 2 1 0
+ 1 5 4 0
__________
4 7 5 0
Step 2 (Subtraction)
Th H T O
1
4 7 5 0
-1 5 8 0
___________
3 1 7 0
Ans: 3170
Word Problem:
Q.1. Jamnalal a fruit seller had 560 Kg of apples. He sold 385 Kg during the day. How many apples are
left with him?
Sol 1 Apples with Jamnalal
=
560 Kg
Apples sold during the day
=
385 Kg
Apples left with him
=
560 – 385 = 175
Ans- Jamnalal has 175 Kgs left.
Q.2. How much should be subtracted from the largest four digit number to get the smallest four digit
number?
Sol2 – The largest four digit number
=
9999
The smallest four digit number =
1000
Difference
9999-1000 = 8999
=
Ans- 8999 should be subtracted.
Mental Maths
1. The difference between the smallest and the greatest 3 digit number
Is?
2. If 13 are subtracted from a number it gives 50, Find the number.
3. The difference between 1000 and 1001 is?
4. 10 less than 365 is
5. 8000 + 2000 - 5000 =
6. 1225 - _____ = 1225
7. 16 – 0 =
8. 1008 - 8 =
9. 2569
- ______= 0
10. 1000 - 999 = ________