Addition — Grade 4 Mathematics
In Grade 4, we extend column addition to 5-digit and larger numbers, develop efficient mental methods (near doubles, partitioning, compensation), and tackle multi-step problems involving decimals and money.
Mental Addition Methods
Near Doubles: 48 + 49 = double 48 + 1 = 96 + 1 = 97
Compensation: 2 463 + 1 999 = 2 463 + 2 000 − 1 = 4 463 − 1 = 4 462
Partitioning: 3 456 + 2 123 = (3 000+2 000) + (400+100) + (50+20) + (6+3) = 5 579
Compensation: 2 463 + 1 999 = 2 463 + 2 000 − 1 = 4 463 − 1 = 4 462
Partitioning: 3 456 + 2 123 = (3 000+2 000) + (400+100) + (50+20) + (6+3) = 5 579
💡 Choose your method: For numbers close to a round number, compensation is fastest. For exact column work, use written method.
Worked Examples
Example 1 — 5-Digit Column Addition
Calculate 24 856 + 37 469
TTh Th H T O
1 1 1 1
2 4 8 5 6
+ 3 7 4 6 9
6 2 3 2 5
+ 3 7 4 6 9
6 2 3 2 5
- O: 6+9=15 → write 5, carry 1
- T: 5+6+1=12 → write 2, carry 1
- H: 8+4+1=13 → write 3, carry 1
- Th: 4+7+1=12 → write 2, carry 1
- TTh: 2+3+1=6
- Answer: 62 325
Example 2 — Adding Decimals (Money)
A computer costs £549.95. A printer costs £87.50. What is the total cost?
- Line up decimal points: 549.95 + 87.50
- = £549.95 + £87.50 = £637.45
Example 3 — Real World: City Population 🏙️
City A has 48 372 people. City B has 36 915. City C has 21 804. What is the combined population?
- 48 372 + 36 915 = 85 287
- 85 287 + 21 804 = 107 091
Practice Questions
1. Calculate 36 482 + 25 739.
✅ 62 221
2. Use compensation to add 4 567 + 2 998.
✅ 4 567 + 3 000 − 2 = 7 565
3. A shop sells 12 456 items in January and 18 739 in February. How many in total?
✅ 12 456 + 18 739 = 31 195 items
4. Calculate £128.75 + £246.80.
✅ £375.55
5. Three schools have 1 248, 986, and 1 573 pupils. What is the total?
✅ 1 248 + 986 = 2 234; 2 234 + 1 573 = 3 807 pupils
Key Points to Remember
- Always align digits by place value (or decimal points for decimals).
- Compensation: round to a friendly number, add/subtract the adjustment.
- Near doubles: work out double of the smaller, then adjust.
- Carry digits go above the next column to avoid errors.
- Estimate first to check: 36 482 + 25 739 ≈ 36 000 + 26 000 = 62 000 ✓