Maths

Addition and Subtraction

Class 3

🎯 Learning Objectives

πŸ“– Let Us Begin!

Meena's school collected 347 books in the first week and 285 books in the second week for a book donation drive. How many books were collected in all? To find out, we add the two numbers.

Sometimes when we add, the total in a column is more than 9. Then we carry the extra to the next column. This is called regrouping.

If the school gave away 268 books from a stock of 503, how many are left? We subtract. Sometimes the top digit is smaller, so we borrow from the next column.

Step-by-Step: Addition with Carrying

Example 1: 347 + 285

HTO
347
+285
=632

Step 1 (Ones): 7 + 5 = 12. Write 2 in the Ones column. Carry 1 to the Tens column.

Step 2 (Tens): 4 + 8 = 12, plus the carried 1 = 13. Write 3 in the Tens column. Carry 1 to the Hundreds column.

Step 3 (Hundreds): 3 + 2 = 5, plus the carried 1 = 6. Write 6 in the Hundreds column.

Answer: 347 + 285 = 632

Addition with Carrying: More Examples

Example 2: 456 + 378

Ones: 6 + 8 = 14, write 4, carry 1. Tens: 5 + 7 = 12, + 1 = 13, write 3, carry 1. Hundreds: 4 + 3 = 7, + 1 = 8.

Answer: 456 + 378 = 834

Example 3: 589 + 276

Ones: 9 + 6 = 15, write 5, carry 1. Tens: 8 + 7 = 15, + 1 = 16, write 6, carry 1. Hundreds: 5 + 2 = 7, + 1 = 8.

Answer: 589 + 276 = 865

Visual showing addition with carrying β€” groups of objects being combined with regrouping arrows

4-Digit Addition with Carrying

In Class 3, we also add 4-digit numbers. The method is the same β€” start from the Ones column and move left.

Example 4: 2,456 + 1,378

ThHTO
2456
+1378
=3834

Step 1 (Ones): 6 + 8 = 14. Write 4, carry 1.

Step 2 (Tens): 5 + 7 = 12, + 1 = 13. Write 3, carry 1.

Step 3 (Hundreds): 4 + 3 = 7, + 1 = 8. Write 8.

Step 4 (Thousands): 2 + 1 = 3. Write 3.

Answer: 2,456 + 1,378 = 3,834

Example 5: 4,567 + 3,895

Ones: 7 + 5 = 12, write 2, carry 1. Tens: 6 + 9 = 15, + 1 = 16, write 6, carry 1. Hundreds: 5 + 8 = 13, + 1 = 14, write 4, carry 1. Thousands: 4 + 3 = 7, + 1 = 8.

Answer: 4,567 + 3,895 = 8,462

Step-by-Step: Subtraction with Borrowing

Example 1: 503 − 268

HTO
503
−268
=235

Step 1 (Ones): 3 − 8? We cannot! Borrow 1 ten from the Tens column. But Tens column is 0, so borrow 1 hundred from the Hundreds column first. H becomes 4, T becomes 10. Now borrow 1 ten for Ones: T becomes 9, O becomes 13. Now 13 − 8 = 5.

Step 2 (Tens): 9 − 6 = 3.

Step 3 (Hundreds): 4 − 2 = 2.

Answer: 503 − 268 = 235

Subtraction with Borrowing: More Examples

Example 2: 700 − 356

Ones: 0 − 6? Cannot! Borrow from Tens. Tens is 0, so borrow from Hundreds first. H becomes 6, T becomes 10. Now borrow 1 for Ones: T becomes 9, O becomes 10. 10 − 6 = 4.

Tens: 9 − 5 = 4. Hundreds: 6 − 3 = 3.

Answer: 700 − 356 = 344

Example 3: 812 − 467

Ones: 2 − 7? Cannot! Borrow from Tens: T becomes 0, O becomes 12. 12 − 7 = 5.

Tens: 0 − 6? Cannot! Borrow from Hundreds: H becomes 7, T becomes 10. 10 − 6 = 4.

Hundreds: 7 − 4 = 3.

Answer: 812 − 467 = 345

Visual showing subtraction with borrowing on a number line

4-Digit Subtraction with Borrowing

Example 4: 5,003 − 2,768

ThHTO
5003
−2768
=2235

Step 1 (Ones): 3 − 8? Cannot! Tens is 0, Hundreds is 0. Borrow from Thousands: Th becomes 4, H becomes 10. Now borrow from H for T: H becomes 9, T becomes 10. Now borrow from T for O: T becomes 9, O becomes 13. 13 − 8 = 5.

Step 2 (Tens): 9 − 6 = 3.

Step 3 (Hundreds): 9 − 7 = 2.

Step 4 (Thousands): 4 − 2 = 2.

Answer: 5,003 − 2,768 = 2,235

Example 5: 7,200 − 3,856

Ones: 0 − 6? Cannot! Borrow step by step. T becomes 9, O becomes 10. 10 − 6 = 4.

Tens: 9 − 5 = 4. Hundreds: 1 − 8? Cannot! Borrow from Th: Th becomes 6, H becomes 11. 11 − 8 = 3. Thousands: 6 − 3 = 3.

Answer: 7,200 − 3,856 = 3,344

Checking Subtraction Using Addition

Think: If 503 − 268 = 235, then 235 + 268 should give us back 503. Let us check: 235 + 268 = 503. Correct!

Rule: Difference + Smaller Number = Bigger Number. If this is true, your subtraction is correct.

Check Example

812 − 467 = 345. Check: 345 + 467 = 812 βœ“ Correct!

5,003 − 2,768 = 2,235. Check: 2,235 + 2,768 = 5,003 βœ“ Correct!

Properties of Addition

Addition has some special rules that always work:

PropertyWhat It MeansExample
Commutative Property (Order Property)We can add two numbers in any order and the sum stays the same.347 + 285 = 285 + 347 = 632
Zero Property (Identity Property)Adding 0 to any number gives the same number.456 + 0 = 456
0 + 789 = 789
Associative PropertyWhen adding three numbers, we can group them in any way.(2 + 3) + 4 = 2 + (3 + 4) = 9
Arjun says: "I can add 125 + 300 easily β€” it's 425. So 300 + 125 must also be 425!" He is using the commutative property.

Word Problems (Indian Context)

Problem 1: Money (β‚Ή Rupees)

Ravi's father gave him β‚Ή475 for books and β‚Ή368 for a school bag. How much money did Ravi get in all?

Solution: β‚Ή475 + β‚Ή368 = β‚Ή843. Ravi got β‚Ή843 in all.

Problem 2: Cricket Scores

In a cricket match, India scored 256 runs in the first innings and 189 runs in the second innings. What was the total score?

Solution: 256 + 189 = 445 runs.

Problem 3: Train Passengers

A train had 1,250 passengers. At Delhi station, 486 passengers got down. How many passengers are still on the train?

Solution: 1,250 − 486 = 764 passengers are still on the train.

Problem 4: School Library

Meena's school library has 2,345 Hindi books and 1,678 English books. How many books are there in all?

Solution: 2,345 + 1,678 = 4,023 books in all.

Children at a book donation drive β€” word problem illustration

πŸ“ Key Words

WordMeaning
Carrying (Regrouping)When the sum in a column is 10 or more, we write the ones digit and carry the tens digit to the next column
Borrowing (Regrouping)When the top digit is smaller, we take 1 from the next column to make it bigger
SumThe answer we get after adding
DifferenceThe answer we get after subtracting
Place ValueThe value of a digit based on its position (Ones, Tens, Hundreds, Thousands)
Commutative PropertyNumbers can be added in any order: a + b = b + a
Zero PropertyAdding 0 to any number gives the same number
⭐ Key Points to Remember

Finished learning? Now test what you know!