Subtraction of 3-Digit Numbers
Subtraction of 3-digit numbers means finding the difference between two 3-digit numbers. The larger number is called the minuend, the number being subtracted is the subtrahend, and the result is the difference.
Subtraction can be done with or without regrouping (borrowing). We always subtract from right to left: ones first, then tens, then hundreds.
What is Subtraction of 3-Digit Numbers - Class 3 Maths (Addition and Subtraction (Grade 3))?
Minuend − Subtrahend = Difference
Steps for 3-digit subtraction:
- Write the larger number on top and align ones, tens, and hundreds.
- Subtract the ones column. If the top digit is smaller, borrow from the tens.
- Subtract the tens column. If the top digit is smaller, borrow from the hundreds.
- Subtract the hundreds column.
Solved Examples
Example 1: Subtraction Without Regrouping
Question: Subtract 642 − 321.
Think:
- Ones: 2 − 1 = 1
- Tens: 4 − 2 = 2
- Hundreds: 6 − 3 = 3
Answer: 642 − 321 = 321
Example 2: Subtraction With Regrouping in Ones
Question: Subtract 534 − 267.
Think:
- Ones: 4 − 7 → cannot subtract, borrow 1 ten → 14 − 7 = 7
- Tens: 2 (after borrowing) − 6 → cannot subtract, borrow 1 hundred → 12 − 6 = 6
- Hundreds: 4 (after borrowing) − 2 = 2
Answer: 534 − 267 = 267
Example 3: Subtraction With Regrouping in Tens
Question: Subtract 726 − 381.
Think:
- Ones: 6 − 1 = 5
- Tens: 2 − 8 → cannot subtract, borrow 1 hundred → 12 − 8 = 4
- Hundreds: 6 (after borrowing) − 3 = 3
Answer: 726 − 381 = 345
Example 4: Subtraction from a Round Number
Question: Subtract 500 − 237.
Think:
- Ones: 0 − 7 → borrow from tens, but tens is also 0
- Borrow from hundreds: 500 becomes 4 hundreds, 10 tens
- Now borrow from tens: 10 tens → 9 tens, ones become 10
- Ones: 10 − 7 = 3
- Tens: 9 − 3 = 6
- Hundreds: 4 − 2 = 2
Answer: 500 − 237 = 263
Example 5: Word Problem — Remaining Mangoes
Question: A fruit seller had 845 mangoes. He sold 378 mangoes. How many are left?
Think:
- 845 − 378
- Ones: 5 − 8 → borrow → 15 − 8 = 7
- Tens: 3 (after borrowing) − 7 → borrow → 13 − 7 = 6
- Hundreds: 7 (after borrowing) − 3 = 4
Answer: 467 mangoes are left.
Example 6: Word Problem — Money Spent
Question: Aditi had ₹750. She spent ₹486 on books. How much money is left?
Think:
- 750 − 486
- Ones: 0 − 6 → borrow → 10 − 6 = 4
- Tens: 4 (after borrowing) − 8 → borrow → 14 − 8 = 6
- Hundreds: 6 (after borrowing) − 4 = 2
Answer: Aditi has ₹264 left.
Example 7: Finding the Difference
Question: Find the difference between 903 and 548.
Think:
- Ones: 3 − 8 → borrow → 13 − 8 = 5
- Tens: 9 (after borrowing) − 4 = 5
- Hundreds: 9 − 5 = 4 → wait, hundreds: 9-0 after borrow...
- Let me redo: 903 − 548
- Ones: 3 − 8 → borrow from tens: 0 tens → borrow from hundreds
- 9 hundreds → 8 hundreds, 10 tens → 9 tens and 13 ones
- Ones: 13 − 8 = 5
- Tens: 9 − 4 = 5
- Hundreds: 8 − 5 = 3
Answer: 903 − 548 = 355
Example 8: Checking with Addition
Question: Subtract 862 − 375 and check your answer.
Think:
- Ones: 2 − 5 → borrow → 12 − 5 = 7
- Tens: 5 (after borrow) − 7 → borrow → 15 − 7 = 8
- Hundreds: 7 (after borrow) − 3 = 4
- Answer: 487
- Check: 487 + 375 = 862 ✓
Answer: 862 − 375 = 487
Example 9: Word Problem — Students Absent
Question: A school has 674 students. On one day, 589 were present. How many were absent?
Think:
- 674 − 589
- Ones: 4 − 9 → borrow → 14 − 9 = 5
- Tens: 6 (after borrow) − 8 → borrow → 16 − 8 = 8
- Hundreds: 5 (after borrow) − 5 = 0
Answer: 85 students were absent.
Example 10: Subtracting Equal Numbers
Question: Subtract 456 − 456.
Think:
- Any number minus itself = 0
Answer: 456 − 456 = 0
Real-World Applications
Where is 3-digit subtraction used?
- Money: 'I had ₹800 and spent ₹545. How much is left?' → 800 − 545 = 255.
- Shopping: 'The MRP is ₹999 and the discount is ₹150. What is the selling price?' → 999 − 150 = 849.
- Distance: 'Total distance is 500 km. We have driven 325 km. How far to go?' → 500 − 325 = 175.
- Attendance: 'School has 674 students. 589 are present. How many are absent?' → 674 − 589 = 85.
- Score difference: 'India scored 356, Australia scored 289. By how much did India win?' → 356 − 289 = 67.
Subtraction is used whenever we need to find what is left, find a difference, or compare two quantities. It is one of the four basic operations and appears in countless daily situations.
Key Points to Remember
- Always subtract column by column from right to left.
- If the top digit is smaller, borrow (regroup) from the next column.
- When borrowing from a zero, go to the next non-zero digit.
- Check subtraction by adding: Difference + Subtrahend = Minuend.
- The difference between two equal numbers is always 0.
- Subtracting 0 from any number gives the same number.
Practice Problems
- Subtract 875 − 432.
- Subtract 600 − 347.
- Subtract 503 − 268.
- Ria had ₹925. She spent ₹478. How much is left?
- Find the difference between 701 and 356.
- Subtract 999 − 1.
- A garden has 548 plants. 269 are flowering. How many are not flowering?
Frequently Asked Questions
Q1. What is regrouping in subtraction?
Regrouping (borrowing) happens when the top digit is smaller than the bottom digit in a column. You borrow 1 from the next place to the left, adding 10 to the current place.
Q2. How do you subtract from a number with zeros like 700?
When the tens digit is 0, you cannot borrow from it directly. First borrow from the hundreds (700 becomes 6 hundreds and 10 tens), then borrow from the tens for the ones column.
Q3. How do you check a subtraction answer?
Add the difference and the subtrahend. If the result equals the minuend, your answer is correct. For example, 845 − 378 = 467; check: 467 + 378 = 845.
Q4. Can the answer to 3-digit subtraction be a 2-digit or 1-digit number?
Yes. For example, 674 − 589 = 85 (2-digit), and 501 − 498 = 3 (1-digit).
Q5. What is the difference between subtraction and addition?
Addition finds the total of two or more numbers. Subtraction finds how much is left or the difference between two numbers. They are inverse operations.
Q6. What if I subtract a larger number from a smaller number?
In Class 3, we always subtract the smaller number from the larger number. Subtracting a larger number from a smaller one gives a negative number, which is studied in higher classes.
Q7. What clue words tell me to subtract?
Words like 'left', 'remaining', 'difference', 'how many more', 'how many fewer', 'less than', and 'took away' indicate subtraction.
Q8. Is subtraction commutative like addition?
No. Changing the order in subtraction changes the answer. 500 − 200 = 300, but 200 − 500 is not the same. Subtraction is not commutative.
Related Topics
- Addition of 3-Digit Numbers
- Subtraction Word Problems (Grade 3)
- Addition Without Regrouping (3-Digit)
- Addition With Regrouping (3-Digit)
- Addition Word Problems (Grade 3)
- Subtraction With Regrouping (3-Digit)
- Subtraction Without Regrouping (3-Digit)
- Mental Math (Grade 3)
- Adding 4 or More Numbers
- Checking Addition and Subtraction
- Mixed Operations (Grade 3)
- Mixed Word Problems (Grade 3)
