📚 Detailed Explanation: Subtracting Three-Digit Numbers with Regrouping
When we subtract three-digit numbers with regrouping, it means we need to borrow tens or hundreds to make the subtraction easier. This is called regrouping or borrowing. Let’s learn how to subtract three-digit numbers step-by-step!
Step 1: Write the Numbers in Columns
Write the bigger number on top and the smaller number below it. Make sure the hundreds, tens, and units (ones) are lined up correctly.
524 - 278
Step 2: Start with the Units (Ones) Column
Look at the units column. Can you subtract the bottom digit from the top digit?
For 4 − 8, we can’t subtract 8 from 4 because 4 is smaller. So, we need to regroup!
Step 3: Regroup from the Tens Column
Take 1 ten (which is 10) from the tens column and add it to the units column.
- The tens digit in 524 is 2 (which means 20).
- Reduce the tens digit by 1 (2 becomes 1).
- Add 10 to the units digit: 4 + 10 = 14 units.
Now subtract: 14 − 8 = 6.
Step 4: Move to the Tens Column
Now look at the tens column: 1 − 7
Again, 1 is smaller than 7, so we regroup again from the hundreds column.
- Take 1 hundred (which is 100) from the hundreds column.
- The hundreds digit 5 becomes 4.
- Add 10 tens to the tens column: 1 + 10 = 11 tens.
Subtract: 11 − 7 = 4.
Step 5: Move to the Hundreds Column
Now subtract the hundreds column: 4 − 2 = 2.
Step 6: Write the Answer
Put the digits from each column together: 2 (hundreds), 4 (tens), and 6 (units).
The final answer is 246.
Another Example
703 - 459
- Units: 3 − 9? No, so regroup 1 ten from 0 tens (no tens here!).
- Regroup from hundreds: 7 hundreds becomes 6 hundreds, and 0 tens becomes 10 tens.
- Now regroup 1 ten from 10 tens to units: units = 3 + 10 = 13, tens = 9.
- Units: 13 − 9 = 4
- Tens: 9 − 5 = 4
- Hundreds: 6 − 4 = 2
Answer: 244
📝 Tips to Remember When Subtracting Three-Digit Numbers with Regrouping:
- Always start subtracting from the right (units/ones column).
- If the top digit is smaller, borrow from the next column to the left.
- Remember to reduce the number you borrowed from by 1.
- Take your time and check each step carefully.
Practice using these steps, and soon subtracting three-digit numbers with regrouping will be easy! 🎉
🧮 20 Examination-Style Questions on Subtracting Three-Digit Numbers with Regrouping
Here are 20 examination-style questions to help Year 3 students practise subtracting three-digit numbers with regrouping. These questions have a mix of difficulty levels to test your understanding of subtracting numbers with regrouping.
Questions
- 423 − 178 = ______
- 561 − 294 = ______
- 732 − 486 = ______
- 859 − 473 = ______
- 605 − 389 = ______
- 947 − 268 = ______
- 814 − 395 = ______
- 630 − 285 = ______
- 754 − 367 = ______
- 893 − 479 = ______
- 925 − 438 = ______
- 780 − 394 = ______
- 646 − 275 = ______
- 832 − 459 = ______
- 540 − 376 = ______
- 667 − 298 = ______
- 715 − 639 = ______
- 801 − 275 = ______
- 979 − 684 = ______
- 832 − 498 = ______
Use your regrouping skills to carefully subtract each number. Remember to start subtracting from the ones column and regroup if needed from the tens or hundreds! ✅
✅ Answers to 20 Examination-Style Questions on Subtracting Three-Digit Numbers with Regrouping
Here are the answers with clear working steps showing how to subtract three-digit numbers with regrouping. Each question helps Year 3 students understand how to exchange tens and hundreds when needed.
Question 1: 423 − 178
Step 1: Start with the units column: 3 – 8 (can’t do, regroup)
Step 2: Regroup 1 ten from the tens column (2 tens become 1 ten, units become 13)
Step 3: 13 – 8 = 5
Step 4: Tens: 1 – 7 (can’t do, regroup)
Step 5: Regroup 1 hundred from the hundreds column (4 hundreds become 3 hundreds, tens become 11 tens)
Step 6: 11 – 7 = 4
Step 7: Hundreds: 3 – 1 = 2
Answer: 245
Question 2: 561 − 294
Units: 1 – 4 (need regroup)
Regroup 1 ten (6 tens become 5 tens, units become 11)
11 – 4 = 7
Tens: 5 – 9 (need regroup)
Regroup 1 hundred (5 hundreds become 4 hundreds, tens become 15)
15 – 9 = 6
Hundreds: 4 – 2 = 2
Answer: 267
Question 3: 732 − 486
Units: 2 – 6 (need regroup)
Regroup 1 ten (3 tens become 2 tens, units become 12)
12 – 6 = 6
Tens: 2 – 8 (need regroup)
Regroup 1 hundred (7 hundreds become 6 hundreds, tens become 12)
12 – 8 = 4
Hundreds: 6 – 4 = 2
Answer: 246
Question 4: 859 − 473
Units: 9 – 3 = 6
Tens: 5 – 7 (need regroup)
Regroup 1 hundred (8 hundreds become 7 hundreds, tens become 15)
15 – 7 = 8
Hundreds: 7 – 4 = 3
Answer: 386
Question 5: 605 − 389
Units: 5 – 9 (need regroup)
Regroup 1 ten (0 tens cannot, regroup 1 hundred)
Hundreds 6 become 5, tens 10
Regroup 1 ten to units: units 15
15 – 9 = 6
Tens: 9 – 8 = 1
Hundreds: 5 – 3 = 2
Answer: 216
Question 6: 947 − 268
Units: 7 – 8 (need regroup)
Regroup 1 ten (4 tens become 3 tens, units become 17)
17 – 8 = 9
Tens: 3 – 6 (need regroup)
Regroup 1 hundred (9 hundreds become 8 hundreds, tens become 13)
13 – 6 = 7
Hundreds: 8 – 2 = 6
Answer: 679
Question 7: 814 − 395
Units: 4 – 5 (need regroup)
Regroup 1 ten (1 ten becomes 0 tens, units become 14)
14 – 5 = 9
Tens: 0 – 9 (need regroup)
Regroup 1 hundred (8 hundreds become 7 hundreds, tens become 10)
10 – 9 = 1
Hundreds: 7 – 3 = 4
Answer: 419
Question 8: 630 − 285
Units: 0 – 5 (need regroup)
Regroup 1 ten (3 tens become 2 tens, units become 10)
10 – 5 = 5
Tens: 2 – 8 (need regroup)
Regroup 1 hundred (6 hundreds become 5 hundreds, tens become 12)
12 – 8 = 4
Hundreds: 5 – 2 = 3
Answer: 345
Question 9: 754 − 367
Units: 4 – 7 (need regroup)
Regroup 1 ten (5 tens become 4 tens, units become 14)
14 – 7 = 7
Tens: 4 – 6 (need regroup)
Regroup 1 hundred (7 hundreds become 6 hundreds, tens become 14)
14 – 6 = 8
Hundreds: 6 – 3 = 3
Answer: 387
Question 10: 893 − 479
Units: 3 – 9 (need regroup)
Regroup 1 ten (9 tens become 8 tens, units become 13)
13 – 9 = 4
Tens: 8 – 7 = 1
Hundreds: 8 – 4 = 4
Answer: 414
Question 11: 925 − 438
Units: 5 – 8 (need regroup)
Regroup 1 ten (2 tens become 1 ten, units become 15)
15 – 8 = 7
Tens: 1 – 3 (need regroup)
Regroup 1 hundred (9 hundreds become 8 hundreds, tens become 11)
11 – 3 = 8
Hundreds: 8 – 4 = 4
Answer: 487
Question 12: 780 − 394
Units: 0 – 4 (need regroup)
Regroup 1 ten (8 tens become 7 tens, units become 10)
10 – 4 = 6
Tens: 7 – 9 (need regroup)
Regroup 1 hundred (7 hundreds become 6 hundreds, tens become 17)
17 – 9 = 8
Hundreds: 6 – 3 = 3
Answer: 386
Question 13: 646 − 275
Units: 6 – 5 = 1
Tens: 4 – 7 (need regroup)
Regroup 1 hundred (6 hundreds become 5 hundreds, tens become 14)
14 – 7 = 7
Hundreds: 5 – 2 = 3
Answer: 371
Question 14: 832 − 459
Units: 2 – 9 (need regroup)
Regroup 1 ten (3 tens become 2 tens, units become 12)
12 – 9 = 3
Tens: 2 – 5 (need regroup)
Regroup 1 hundred (8 hundreds become 7 hundreds, tens become 12)
12 – 5 = 7
Hundreds: 7 – 4 = 3
Answer: 373
Question 15: 540 − 376
Units: 0 – 6 (need regroup)
Regroup 1 ten (4 tens become 3 tens, units become 10)
10 – 6 = 4
Tens: 3 – 7 (need regroup)
Regroup 1 hundred (5 hundreds become 4 hundreds, tens become 13)
13 – 7 = 6
Hundreds: 4 – 3 = 1
Answer: 164
Question 16: 667 − 298
Units: 7 – 8 (need regroup)
Regroup 1 ten (6 tens become 5 tens, units become 17)
17 – 8 = 9
Tens: 5 – 9 (need regroup)
Regroup 1 hundred (6 hundreds become 5 hundreds, tens become 15)
15 – 9 = 6
Hundreds: 5 – 2 = 3
Answer: 369
Question 17: 715 − 639
Units: 5 – 9 (need regroup)
Regroup 1 ten (1 ten becomes 0 tens, units become 15)
15 – 9 = 6
Tens: 0 – 3 (need regroup)
Regroup 1 hundred (7 hundreds become 6 hundreds, tens become 10)
10 – 3 = 7
Hundreds: 6 – 6 = 0
Answer: 76
Question 18: 801 − 275
Units: 1 – 5 (need regroup)
Regroup 1 ten (0 tens can’t, regroup 1 hundred)
Hundreds 8 become 7, tens 10
Regroup 1 ten to units: units 11
11 – 5 = 6
Tens: 9 – 7 = 2
Hundreds: 7 – 2 = 5
Answer: 526
Question 19: 979 − 684
Units: 9 – 4 = 5
Tens: 7 – 8 (need regroup)
Regroup 1 hundred (9 hundreds become 8 hundreds, tens become 17)
17 – 8 = 9
Hundreds: 8 – 6 = 2
Answer: 295
Question 20: 832 − 498
Units: 2 – 8 (need regroup)
Regroup 1 ten (3 tens become 2 tens, units become 12)
12 – 8 = 4
Tens: 2 – 9 (need regroup)
Regroup 1 hundred (8 hundreds become 7 hundreds, tens become 12)
12 – 9 = 3
Hundreds: 7 – 4 = 3
Answer: 334
These answers include clear steps on how to regroup hundreds and tens when subtracting three-digit numbers. Practising these methods helps Year 3 students master subtracting with regrouping confidently! 💪📊
