Addition — Grade 3 Mathematics
In Grade 3, we extend column addition to 3 and 4-digit numbers, handle multiple carries, add more than two numbers at once, and apply addition to multi-step word problems.
Place Value and Column Addition
Line up digits by place value — Thousands (Th), Hundreds (H), Tens (T), Ones (O).
Always add from right to left (O → T → H → Th).
If the sum in a column is 10 or more, write the ones digit and carry 1 to the next column.
Always add from right to left (O → T → H → Th).
If the sum in a column is 10 or more, write the ones digit and carry 1 to the next column.
💡 Tip: Write carries in small numbers above the column they belong to — it prevents mistakes!
Worked Examples
Example 1 — 3-Digit Column Addition
Calculate 4 7 6 + 3 5 8
H T O
1 1
4 7 6
+ 3 5 8
8 3 4
+ 3 5 8
8 3 4
- O: 6 + 8 = 14 → write 4, carry 1
- T: 7 + 5 + 1 = 13 → write 3, carry 1
- H: 4 + 3 + 1 = 8
- Answer: 834
Example 2 — 4-Digit Column Addition
Calculate 2 4 8 7 + 1 6 3 5
Th H T O
1 1
2 4 8 7
+ 1 6 3 5
4 1 2 2
+ 1 6 3 5
4 1 2 2
- O: 7 + 5 = 12 → write 2, carry 1
- T: 8 + 3 + 1 = 12 → write 2, carry 1
- H: 4 + 6 + 1 = 11 → write 1, carry 1
- Th: 2 + 1 + 1 = 4
- Answer: 4 122
Example 3 — Real World: Library Book Count 📚
A library has 1 345 fiction books, 892 non-fiction books, and 416 picture books. How many books in total?
- Step 1: 1 345 + 892 = 2 237
- Step 2: 2 237 + 416 = 2 653
The library has 2 653 books in total.
Practice Questions
1. Calculate 563 + 274.
✅ 837 (O:7, T:3+7+1=11→1 carry 1, H:5+2+1=8)
2. Calculate 1 742 + 2 589.
✅ 4 331
3. A school sells 856 tickets on Saturday and 1 247 on Sunday. How many tickets in total?
✅ 856 + 1 247 = 2 103 tickets
4. What is 3 456 + 4 789?
✅ 8 245
5. Three classes raise: £124, £237, and £409. What is the total raised?
✅ 124 + 237 = 361; 361 + 409 = £770
Key Points to Remember
- Line up digits by place value before adding.
- Add from right to left: Ones → Tens → Hundreds → Thousands.
- If a column sums to ≥ 10: write the ones digit and carry the tens digit.
- For multi-step problems, highlight key numbers and add in stages.
- Estimate first (round to nearest hundred) to check your answer is reasonable.