Column subtraction – Grade 4
Learn column subtraction by regrouping, including zeros and checking with addition. Create a free worksheet or try an online test.
🎯 What you will learn
- ✓Align place values
- ✓Regroup across a zero
💡 How it works
You know ones, tens and hundreds. Exchanging one ten for ten ones keeps the value of the number unchanged.
How it works
💡 Work right to left. If there are too few ones, exchange a ten and record both changes.
Align ones under ones and tens under tens. In 452 − 178, 2 ones are not enough to subtract 8. The 5 tens become 4 tens and the 2 ones become 12 ones. Now calculate 12 − 8.
If the next place is zero, go to the next nonzero place. For 603, exchange a hundred for 10 tens, then a ten for 10 ones. You have 5 hundreds, 9 tens and 13 ones, still worth 603.
🧩 See the method
✍️ Worked examples
Worked examples 1
452 − 178
- 1.Ones: 12 − 8 = 4; 4 tens remain.
- 2.Tens: regroup again, 14 − 7 = 7.
- 3.Hundreds: 3 − 1 = 2. Check: 274 + 178 = 452.
✓ 274
Worked examples 2
603 − 287
- 1.Regroup: 603 = 500 + 90 + 13.
- 2.Ones: 13 − 7 = 6. Tens: 9 − 8 = 1.
- 3.Hundreds: 5 − 2 = 3. Check: 316 + 287 = 603.
✓ 316
⚠️ Common mistakes
- • Subtracting the top digit from the bottom one because it is smaller. Regroup instead.
- • Forgetting to reduce the tens. Regrouping changes two places.
📝 Try it yourself
1.
584 − 231
Show answer
353
2.
742 − 368
Show answer
374
3.
500 − 246
Show answer
254
4.
806 − 479
Show answer
327
5.
931 − 587
Show answer
344
6.
1000 − 648
Show answer
352
Create matching questions
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FAQ
What if the next digit is zero?
Regroup from the next nonzero place, as in 603 = 500 + 90 + 13.
Are there other written methods?
Yes, such as counting up. Here we use regrouping. Do not mix the notation of different methods in one problem.