Primary 3 Addition and Subtraction (up to 4 digits)
Line up digits by place value. Add with carrying or subtract with exchanging, then check the answer using the inverse operation.
Keywords
- Sum
- The answer to an addition.
- Difference
- The answer to a subtraction.
- Carry
- Move 1 to the next place when an addition column makes 10 or more.
- Exchange
- Rename 1 from a larger place as 10 of the next smaller place.
- Inverse
- The opposite operation used to check an answer: addition and subtraction undo each other.
Addition up to 4 digits
Write ones under ones, tens under tens, and so on. Add from the ones place. If a column totals 10 or more, write its ones digit and carry 1 to the next place.
2 468 + 1 357 = ?
| Thousands | Hundreds | Tens | Ones | |
|---|---|---|---|---|
| Regroup | ||||
| 2 | 4 | 6 | 8 | |
| + | 1 | 3 | 5 | 7 |
| Answer |
Start at the ones place.
See worked example
Add 2 468 and 1 357.
- Ones: 8 + 7 = 15. Write 5 ones and carry 1 ten.
- Tens: 6 + 5 + 1 = 12. Write 2 tens and carry 1 hundred.
- Hundreds: 4 + 3 + 1 = 8. Thousands: 2 + 1 = 3.
- Check: 3 825 − 1 357 = 2 468.
Answer: 2 468 + 1 357 = 3 825.
Try together
Work out 3 785 + 2 467, then check by subtraction.
Reveal the answer
6 252. Check: 6 252 − 2 467 = 3 785.
Subtraction up to 4 digits
Line up the places and subtract from the ones place. If the top digit is too small, exchange 1 from a larger place. A zero may make the exchange travel across several places.
5 003 − 1 568 = ?
| Thousands | Hundreds | Tens | Ones | |
|---|---|---|---|---|
| Regroup 3 | ||||
| Regroup 2 | ||||
| Regroup 1 | ||||
| 5 | 0 | 0 | 3 | |
| − | 1 | 5 | 6 | 8 |
| Answer |
The ones need regrouping. Show each exchange before subtracting.
See worked example
Subtract 1 568 from 5 003.
- The 3 ones cannot take away 8 ones. Exchange through the two zero places: 5 003 becomes 4 thousands, 9 hundreds, 9 tens and 13 ones.
- Subtract the ones and tens: 13 − 8 = 5; 9 − 6 = 3.
- Subtract the hundreds and thousands: 9 − 5 = 4; 4 − 1 = 3.
- Check: 3 435 + 1 568 = 5 003.
Answer: 5 003 − 1 568 = 3 435.
Try together
Work out 4 002 − 1 745, then check by addition.
Reveal the answer
2 257. Check: 2 257 + 1 745 = 4 002.